Refactor e2e unit tests

[pmachapman]

Fixes #765 and #784.

This is not a complete refactor of all of the tests, but I have simplified use of Paratext projects in e2e tests, which should make future tests easier. I've also updated the test data to be public domain data for both Paratext and text files.

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This change is 

[Enkidu93]

Sorry for taking a while to get to this! Thank you for doing this, Peter!

@Enkidu93 reviewed 52 of 52 files at r1, all commit messages.
Reviewable status: all files reviewed, 8 unresolved discussions (waiting on @ddaspit)

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src/Serval/test/Serval.E2ETests/data/TestProject/grc.ldml line 0 at r1 (raw file):
Do we need to check this in?

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src/Serval/test/Serval.E2ETests/ServalClientHelper.cs line 593 at r1 (raw file):

        var sourceFileConfig = new List<CorpusFileConfig>();

        if (sourceLanguage == targetLanguage && !inference)

This logic always felt a little awkward to me. At a minimum, since this is used a few times, could we move it to a method?

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src/Serval/test/Serval.E2ETests/data/sbp_usfm/sbp.ldml line 0 at r1 (raw file):
Do we need to check this in for our purposes? Or can we just remove it?

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src/Serval/test/Serval.E2ETests/ServalApiTests.cs line 221 at r1 (raw file):

            }
        ];
        await StartAndCancelTwiceAsync(engineId);

Could we just do the StartAndCancelTwice() as part of another test and then go on to run it as usual? It probably wouldn't save a ton of time, but it would be something.

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src/Serval/test/Serval.E2ETests/ServalApiTests.cs line 225 at r1 (raw file):

    [Test]
    public async Task Nmt_LargeBatchAndDownload()

Could this be combined with Nmt_Batch?

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src/Serval/test/Serval.E2ETests/ServalApiTests.cs line 504 at r1 (raw file):

        await _helperClient.AddParatextCorpusToEngineAsync(engineId, "es", "en", false);

        await StartAndCancelTwiceAsync(engineId);

See comment above.

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src/Serval/test/Serval.E2ETests/data/en_usfm/en.ldml line 1 at r1 (raw file):

<ldml><identity><version number="" /><generation date="2018-04-03T20:44:50Z" /><language type="en" /><special xmlns:sil="urn://www.sil.org/ldml/0.1"><sil:identity windowsLCID="1033" /></special></identity><characters><exemplarCharacters>[A-Za-z]</exemplarCharacters><exemplarCharacters type="punctuation">[!'-),-.\:;?\[\]\u00B4\u200C\u200D\u2014\u2018\u2019\u201C\u201D]</exemplarCharacters><special xmlns:sil="urn://www.sil.org/ldml/0.1"><sil:exemplarCharacters type="wordFormingPunctuation">['\-\u00B4\u2014]</sil:exemplarCharacters><sil:exemplarCharacters type="footnotes">[]</sil:exemplarCharacters><sil:exemplarCharacters type="crossrefs">[]</sil:exemplarCharacters><sil:exemplarCharacters type="verseSegments">[a b c d e f g h i j k l m n o p q r s t u v w x y z {aa} {bb} {cc} {dd} {ee} {ff} {gg} {hh} {ii} {jj} {kk} {ll} {mm} {nn} {oo} {pp} {qq} {rr} {ss} {tt} {uu} {vv} {ww} {xx} {yy} {zz}]</sil:exemplarCharacters><sil:exemplarCharacters type="diacritics">[]</sil:exemplarCharacters><sil:exemplarCharacters type="wordBreaks">[]</sil:exemplarCharacters></special></characters><delimiters><quotationStart>“</quotationStart><quotationEnd>”</quotationEnd><alternateQuotationStart>‘</alternateQuotationStart><alternateQuotationEnd>’</alternateQuotationEnd><special xmlns:sil="urn://www.sil.org/ldml/0.1"><sil:matched-pairs><sil:matched-pair open="(" close=")" paraClose="false" /><sil:matched-pair open="[" close="]" paraClose="false" /><sil:matched-pair open="{" close="}" paraClose="false" /></sil:matched-pairs><sil:punctuation-patterns><sil:punctuation-pattern pattern="._" context="final" /><sil:punctuation-pattern pattern="!_" context="final" /><sil:punctuation-pattern pattern="?_" context="final" /><sil:punctuation-pattern pattern="-" context="medial" /><sil:punctuation-pattern pattern="'" context="medial" /><sil:punctuation-pattern pattern="´" context="medial" /><sil:punctuation-pattern pattern="—" context="medial" /><sil:punctuation-pattern pattern="‌" context="medial" /><sil:punctuation-pattern pattern="‍" context="medial" /></sil:punctuation-patterns><sil:quotation-marks paraContinueType="all"><sil:quotationContinue></sil:quotationContinue><sil:quotation open="“" close="”" level="3" /></sil:quotation-marks></special></delimiters><layout><orientation><characterOrder>left-to-right</characterOrder></orientation></layout><collations><defaultCollation>standard</defaultCollation><collation type="standard"><cr><![CDATA[&[before 1] [first regular] < a\/A < b\/B < c\/C < d\/D < e\/E < f\/F < g\/G < h\/H < i\/I < j\/J < k\/K < l\/L < m\/M < n\/N < o\/O < p\/P < q\/Q < r\/R < s\/S < t\/T < u\/U < v\/V < w\/W < x\/X < y\/Y < z\/Z]]></cr><special xmlns:sil="urn://www.sil.org/ldml/0.1"><sil:simple><![CDATA[a/A

Do we need to check this in?

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src/Serval/test/Serval.E2ETests/data/en_usfm/ProjectProgress.xml line 1 at r1 (raw file):

<?xml version="1.0" encoding="utf-8"?>

Same with these: Can we get away with not adding these to the repo?