Clean up ocm github organization teams

[fabianburth]

Why do we need this?

Currently, the team typically used (e.g. for requesting reviews) - Maintainers - also contains the OCM Gear team and other people that do not have to care about this.
Furthermore, there are teams like ocm-cli-team/ocm-cli-admin that are just @fabianburth, @morri-son, and @morrison-sap or ocm-core-team/ocm-core-admin that are just @fabianburth and @morrison-sap.

In conclusion, the teams really need a clean up.

[morri-son]

The project specific Teams have been created by OSPO team by default, when creating new OS repos. I deleted them now as we have teams valid for the whole Org / specific group of repos (OCM Gear Teams). These teams are added to all relevant OCM repos now:

• Admins (Org and repos) with "admin" permission on repos
• Maintainers with "maintain" permission on repos
• Collaborators with "triage" permission on repos

The Admins team has the OSPO team as sub-team, the Collaborators team has the CNLM team and the OCM Gear team as sub-team.

The Maintainers are added as generic CODEOWNERS to all repos, but the .github repo. Inside of .github the CODEOWNERS look like this

# Default owners for everything in the repo.
# Unless a later match takes precedence, the Maintainers team
# will be requested for review when someone opens a pull request.
*       @open-component-model/Maintainers

# Especially for the shared git-repository settings in .github directory
/.github/            @open-component-model/Admins

# Owners for specific directories and files
/.github/workflows/  @open-component-model/Maintainers
/.github/ISSUE_TEMPLATE/  @open-component-model/Maintainers
/.github/pull_request_template.md  @open-component-model/Maintainers

once PR open-component-model/.github#19 has been merged (@fabianburth please do so 😉 and then close this issue. I'll set the status of the issue on the board to "review").