Document HLS triaging process

We are triaging all new issues once a month, but we haven't documented the actual process at the moment.
To ensure that we don't need anyone with prior knowledge to be present at the triaging meeting, let's document or sketch a rough list of todo's for the triaging meeting. This process will be improved over time, so ideally we improve the document over time as well. The document is not intended as a strict instruction set and should still allow some flexibility.

Documentation should include the following checkpoints:
* How to triage with a team
* The last time, one person showed their screen and we discussed what the labels should be for an untriaged issue,
* TODO: what else?