Manual tests migration

See https://forum.xwiki.org/t/manual-tests-vs-automated-tests-analysis/7535 for defining the strategy.

List of the manual tests checked for automated:

P1.Product

http://test.xwiki.org/xwiki/bin/view/Administration%20Tests

https://test.xwiki.org/xwiki/bin/view/Administration%20Tests/Add%20a%20favicon%20for%20the%20wiki - not automated, added JIRA: https://jira.xwiki.org/browse/XWIKI-17911 on 07.10.2020
https://test.xwiki.org/xwiki/bin/view/Administration%20Tests/Add%20Delete%20User%20In%20Group - automated tests exists, updated links to automated tests 14.10.2020
https://test.xwiki.org/xwiki/bin/view/Administration%20Tests/Add%20Subgroup%20To%20Group - automated tests exists, updated links to automated tests 14.10.2020
https://test.xwiki.org/xwiki/bin/view/Administration%20Tests/Administer%20Page%20-%20Presentation%20-%20Change%20Color%20Theme - not automated, added JIRA: https://jira.xwiki.org/browse/XWIKI-17974 on 22.10.2020 - was AUTOMATED
https://test.xwiki.org/xwiki/bin/view/Administration%20Tests/AppWithinMinutes%20parent - asked about it on chat on 27.10.2020