Document our issue triage process

[theunrepentantgeek]

What this PR does / why we need it:

Makes our goal for issue triage public, and documents the GitHub search that we use.

How does this PR make you feel:

If applicable:

• this PR contains documentation

[codecov-commenter]

Codecov Report

Merging #1610 (a5c9d91) into master (0b5e1f2) will not change coverage.
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[matthchr]

Minor, you could rephrase this as:

Suggested change

	On a regular basis (target: weekly) the development team will triage issues matching the following [GitHub search](https://github.com/Azure/azure-service-operator/issues?q=is%3Aissue+is%3Aopen+-label%3Atriaged+no%3Amilestone+):
	On a regular basis (target: weekly) the development team will triage issues matching the following search criteria [is:issue is:open -label:triaged no:milestone](https://github.com/Azure/azure-service-operator/issues?q=is%3Aissue+is%3Aopen+-label%3Atriaged+no%3Amilestone+)

and do away entirely with the ``` section below

[matthchr]

I think this looks a bit cleaner in that it turns the issue criteria into the link rather than having a separate "this search" link

[theunrepentantgeek]

I originally wrote it the way you suggest - but broke it out the way that I did so that the search criteria was more explicitly called out for people to see. Makes it easier to copy too.