Fix some clang tidy warnings

[Xazax-hun]

Mostly adding noexcept to some move assignments/ctors so they are utilized by STL. Also adding some std::move calls to avoid certain potentially expensive copies. Some misc fixes/improvements including fixing typos in comments.

[codecov]

Codecov Report

Attention: Patch coverage is 87.01299% with 10 lines in your changes missing coverage. Please review.

Project coverage is 78.21%. Comparing base (9ac6b24) to head (8016caa).
Report is 38 commits behind head on master.

Files with missing lines	Patch %	Lines
src/include/souffle/utility/FileUtil.h	50.00%	3 Missing ⚠️
src/include/souffle/utility/ParallelUtil.h	33.33%	2 Missing ⚠️
src/ast/Lattice.cpp	0.00%	1 Missing ⚠️
src/ast/analysis/IOType.h	0.00%	1 Missing ⚠️
src/include/souffle/SouffleInterface.h	50.00%	1 Missing ⚠️
src/include/souffle/SymbolTable.h	50.00%	1 Missing ⚠️
...rc/include/souffle/datastructure/RecordTableImpl.h	75.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2464      +/-   ##
==========================================
+ Coverage   78.18%   78.21%   +0.02%     
==========================================
  Files         486      486              
  Lines       32422    32420       -2     
==========================================
+ Hits        25349    25357       +8     
+ Misses       7073     7063      -10     

Files with missing lines	Coverage Δ
src/ast/Constraint.h	100.00% <100.00%> (ø)
src/ast/Lattice.h	100.00% <ø> (ø)
src/ast/Literal.h	100.00% <100.00%> (ø)
src/ast/UnnamedVariable.cpp	100.00% <100.00%> (ø)
src/ast/UserDefinedAggregator.cpp	96.29% <100.00%> (ø)
src/ast/analysis/Aggregate.cpp	99.26% <100.00%> (-0.02%)	⬇️
src/ast/analysis/typesystem/TypeSystem.h	86.01% <100.00%> (ø)
src/ast2ram/utility/ValueIndex.cpp	76.92% <100.00%> (ø)
src/include/souffle/RecordTable.h	100.00% <100.00%> (ø)
src/include/souffle/datastructure/BTree.h	98.12% <100.00%> (ø)
... and 38 more

... and 4 files with indirect coverage changes