Simplify process of adding yourself to the OEO

[l-emele]

Description of the issue

The current process of adding yourself to the OEO is decribed in the wiki. But that process is very complex for newbies that are not familiar with Git/GitHub.

Ideas of solution

One possible solution is to have two possibilities to enter the OEO:

1. The newbie follows the current worklow themself.
2. A newbie will be added by the @OpenEnergyPlatform/oeo-community-manager and/or one of the most experienced oeo-developers like @stap-m or @l-emele.

For option 2, we could create a special issue template where the relevant information (especially for CITATION.cff) is entered.

Workflow checklist

• I am aware of the workflow for this repository

[u-mueller]

@l-emele and @Ludee I added a note to the wiki-page to clarify, that the process that might seem complicated to a newbie (like me:-) is also kind of a driving licence for an OEO contributer, are you ok with that? Maybe we can also delete the first two steps for finding one's ID since they might cause confusion as well (I had two different ID-numbers depending to choose from).

[u-mueller]

Also I think adding option 2 is a good idea, @Ludee

[l-emele]

I opened PR #1525 with an issue template for new users.