* Remove the extra group "Reviewed Pattern Ideas (not yet proven but reviewed)".
Also adapt status in the patterns accordingly.

Rational: 
by definition the 1-Initial patterns don't have a Known Instance yet, i.e. they are not proven. Therefore we don't need an extra group to state this.

* Move all patterns that have a patlet already out of the extra group "Pattern Ideas (not yet proven; brainstormed)".
Those pattern are similar in quality to the ones that we already list in "### Maturity Level 1: Initial", so they don't have to be in an extra group.

* Move remaining patterns from sub-group "Pattern Ideas (not yet proven; brainstormed)" to "Maturity Level 1: Initial".
Also updating the Status in the patterens themselves.

Rational:
* These patterns were not all that different from the ones directl in "Maturity Level 1: Initial".
* Often times they don't have a solution yet, or just a brainstormed solution.
* Many of them don't have a Patlet, likely because they were written at a time when the Pattern Template didn't ask for that yet

* update links to point to files, rather than to PRs

* port the  Donut pattern from old PR #38 into this, so that we can link to the Donut pattern directly, rather than to the PR. Also adapted pattern slightly to fit the current Pattern template better.

* various other smaller fixes

Co-authored-by: Georg Grütter <gruetter@gmail.com>