Improved stats on the GH READMEs

[vmassol]

Hello devs,

FYI, I’ve updated the README.md for xwiki-platform (and I’m doing the same for commons and rendering):

• Added some GH stats (service from https://repobeats.axiom.co/)
• Added contributor icons (service from https://contrib.rocks)
• Reworked some sections

See Comparing 52568521ffc712fd7a69bc4169cad1347793153f..dbdeb34c00005de6171f9b6c8416e416b3965bd0 · xwiki/xwiki-platform · GitHub

If anyone is against this, please let me know.

Thanks

[vmassol]

Also applied for:

• Commons → [Misc] Add stats and rework some sections · xwiki/xwiki-commons@49d739d · GitHub
• Rendering → [Misc] Add stats and rework some sections · xwiki/xwiki-rendering@fe10e07 · GitHub