More flexible repository exclusion (by repo size, time since last commit, fork, and combinations)

Created by: mike-r-mclaughlin

Requested by: https://github.com/sourcegraph/accounts/issues/6716, https://github.com/sourcegraph/accounts/issues/3

Feature request description

All administrators ability to exclude repository based on:

size of repository (e.g., anything greater than x gb)
time since last commit (e.g., exclude any repository that hasn't had a new commit in more than 2 years)
forks (e.g., exclude a repository and all forks)

Additionally it would be great if you could combine these with pattern and repo. For example, it would be nice to exclude a single repository and all of it's forks with something like:

{
   "name": "FOO/bar",
   "forks": true
}

Or, only exclude repositories greater than 10gb in a specific org.

Is your feature request related to a problem? If so, please describe.

Very large scale customers (thousands, 10s of thousands, or 100s of thousands of repositories) often are adding all repositories and then excluding those that some criteria. This feature makes it easier to exclude those repositories by the most common filters (large repositories that likely contain binary files or repos that have had no activity in last x months/years)

See related tickets:

Describe alternatives you've considered.

Write a script to generate the list of repositories outside of Sourcegraph and then add thousands of repositories via name.

/cc @jplahn @ryphil