Add OpenJDK version 15

[MasterEnoc]

• Updated the versions and releases in the scraper file
• Ensured the license is up-to-date and that the documentation's entry in the array in about_tmpl.coffee matches it's data in self.attribution
• Ensured the icons and the SOURCE file in public/icons/your_scraper_name/ are up-to-date if the documentation has a custom icon
• Ensured self.links contains up-to-date urls if self.links is defined
• Tested the changes locally to ensure:
  • The scraper still works without errors
  • The scraped documentation still looks consistent with the rest of DevDocs
  • The categorization of entries is still good

This is a WIP PR, Openjdk 16 still has some style issues.

All the tables are made with 'div' tags rather than table (th, tr, td, etc) tags, this has been painfully hard to work with and I have not found a good way to fix this.

All the other version work as expected and have good styles.

[simon04]

The resulting OpenJDK 16 documentation is very hard to read (for Color):

Should we omit version 16 for now and only add versions 13/14/15?

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Version 15 could get some syntax highlighting as indicated in this screenshot:

[MasterEnoc]

Version 16 removed and syntax highlight improved for version 15.

Notice that syntax highlight in the summary tables can lead to undesirable format (at least using prismjs):

For this reasons syntax highlight was not applied to summary tables.

[simon04]

I've removed versions 13 and 14 since they're end of life and no longer provided on packages.debian.org

[simon04]

Thank you!