CI: ability to combine different types of only/except freely

Problem to solve

I'd like to combined different types of only expressions. For example this step is active for MRs affecting this set of files. Both of those concepts exist, but can not be combined (as far as I can tell).

Target audience

Developer

Further details

In a monorepo setting it would help a lot to be able to have as much flexibility as possible to determine when steps will be running. Using all existing ways in an AND/OR fashion would be a great addition.

Proposal

As mentioned I think if all existing ways to filter could be combined in flexible AND/OR combinations it would add a lot of power. I don't have a proposed syntax, but I can see it would probably need to change a bit from today in order to be nestable and combinable in arbitrary ways.

What does success look like, and how can we measure that?

Success is more power to filter what steps are run for more complicated monorepos.