Rename `prepend_if_ee` to `prepend_mod_with` and unify how we use them [RUN ALL RSPEC] [RUN AS-IF-FOSS]

What does this MR do?

This is a follow up from !57807 (merged) which does:

• Rename prepend_if_ee to prepend_mod_with
• Rename extend_if_ee to extend_mod_with
• Rename include_if_ee to include_mod_with
• Remove ::EE or EE prefix with the module name
• Remove constant_without_prefix after there's no more prefix passed

And additionally, more interesting changes are all in this commit: !61038 (9671f485)

For RuboCop::Cop::InjectEnterpriseEditionModule, we change it that:

• prepend_mod_with must be used for extension modules, therefore we don't need to allow using it on regular modules.

Next up:

• Change prepend_mod_with to use prepend_mod where it fits. It fits when the name passed to it is exactly the same with the module name

Related to #325800 (closed)