Add RFC template repo to pattern

[spier]

I found the repo jakobo/rfc that contains an RFC template. as well as a description of how to run an RFC process internally in an organization.

I suggest we link to this repo from our pattern: https://patterns.innersourcecommons.org/p/transparent-cross-team-decision-making-using-rfcs

We could also check the forks list of the repo, to see if we can identify further adopters of this company-internal RFC approach. Adding those adopters to our pattern would likely require us to contact them and ask if they want to be mentioned publicly.

See related conversation in here.

So the changes could be in two parts (or more):

• [x] add the reference to jakobo/rfc to pattern
• [ ] add further adopters of the RFC approach - based on adopters that we can find via jakobo/rfc