Since docs.typo3.org has been change to https only, adopt all links
in the core as well.

Change-Id: Iaaa1a8277e2b4e1be6c940ef1b6313ea76eba834
Resolves: #68854
Releases: master
Reviewed-on: http://review.typo3.org/42392


Reviewed-by: Xavier Perseguers <xavier@typo3.org>
Tested-by: Xavier Perseguers <xavier@typo3.org>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>

Streamline README.md a bit and add a CONTRIBUTING.md
to hint for basic contribution guidelines.
The CONTRIBUTING.md is especially helpful if the GitHub
repository is forked since GitHub will add a notice with
a link to this file.

Change-Id: I2ff78f72346da4146f6d68777f263d34e0a30a7f
Resolves: #68447
Releases: master
Reviewed-on: http://review.typo3.org/41791


Reviewed-by: Helmut Hummel <helmut.hummel@typo3.org>
Tested-by: Helmut Hummel <helmut.hummel@typo3.org>
Reviewed-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Markus Klein <markus.klein@typo3.org>