Add custom grouping based on filter groups

What does this MR do and why?

Rename file

It's only about filters, specifically SCIM 2.0 filters, so call it that.

Implement custom grouping based on the filter

This borrows code from https://github.com/thomaspoignant/scim2-parse-filter/pull/150, as it hasn't been merged upstream yet.

Closes #135 (closed).

Work around scim2-parse-filter bug

This can be reverted if/when https://github.com/thomaspoignant/scim2-parse-filter/pull/151 is merged.

Give more room for charts

Review/run this locally

1. Copy the pages in mr job URL (must have succeeded)
2. Run bin/review-mr.sh <job url>
3. If there are rules changes, check the compare findings job log reports the expected changes
4. If there are group changes, check the compare groups job log reports the expected changes

Closes #135 (closed)