Offer more control over Github repositories to committers

Currently, committers only have write role on the their projects' Github repositories and project leads have maintainer role.

Maintainers can only configure a limited set of things on the github repositories. For example, managing branch protection rules or configuring tag protection rules are not possible without admin permission. We'd rather not grant admin permission as we would like to keep a tight control over user permissions to ensure compliance with the ECA.

We would like to offer a solution to let projects' committers and PL do more without having to open a help desk ticket every single time.

/cc @gadamsuwr who already has a PoC for this.