Add Watermark to OCA Bundle README and update JSON Index generation script

[swcurran]

Updates the README.md file in all of the OCA Bundle folders to add a Watermark column to the table of identifiers in the file. Set the value to blank if there is no watermark in the related OCABundles.json file, or set the value to be the English ("en") and French ("fr") values found in the OCABundle.json file.

Also updated the script that generates the OCA Bundle index JSON files (ocabundles.json, ocabundleslist.json) to add the watermarks collected per identifier into the indices.

Note that ALL OCA Bundle README files were updated, inlcuding those contributed by others. The intention is that there will NO impact (and this has been tested) on the display of the related credentials.

Next steps:

• Update Bifold/BC Wallet to have the "watermark" value in the index files override those found in the OCABundles.
• Consilidate the OCA Bundles that differ only because of the watermark - e.g. "person" and "person-showcase"

Commits:

• Add Watermark to OCA Bundle README and update JSON Index generation script
• Add empty watermark column to the rest of the READMEs
• Adding empty watermark to last README

[swcurran]

@cvarjao has asked that this be considered from a broader perspective -- can we invest more in the process, so that we can keep the watermark in the OCA Bundle while still reducing the source (Excel) files. For example, perhaps we can inject the watermark into the OCA Bundle at Bundle generation time?

Putting this on hold for now.