Better documentation of ECA process for newcomer

[hendrikebbers]

In the last meeting (https://github.com/adoptium/documentation/issues/29) @Plexar mentioned that he had some problems setting up the system. I Copied the comment from the meeting minutes:

There are some pitfalls for new developers in this project:

• when you claimed an issue by commenting, you should start work on the issue after you have been assigned to be properly mentionned as contributor
• your Eclipse Adoptium email address, your Github email address AND the email address doing a commit with should be equal

[smlambert]

Another potential issue not related to ECA, but to the other comment noted above, is if committers lose the ability to assign people to issues, see: https://bugs.eclipse.org/bugs/show_bug.cgi?id=576856 - Hoping this can be resolved, it just started happening within the last week.

[hendrikebbers]

ouch :( This not happened for the doc repos so far

[hendrikebbers]

See https://github.com/adoptium/documentation/issues/34

[hendrikebbers]

PR merged: https://github.com/adoptium/documentation/pull/38