mimirtool config: GEM conversions & ring.instance_id

[dimitarvdimitrov]

What this PR does

• slightly refactors convert_test.go:
  • it's easier to reuse the logic for adding common flags (e.g. server.http_listen_port and from now also GEM's auth.type)
  • separates some shared test cases (server.http_listen_port)
• updates mimir, cortex, and GEM descriptors:
  • adds hidden config options (e.g. -ingester.lifecycler.id and -distributor.ring.instance_id)
  • replaces the default value of instance_id in GEM and Mimir 2.0 with null - this is done manually until we can support the dynamic flags (ones that detect the default value automatically)
  • updates the GEM descriptor to one from master
• adds support for the rest of the GEM flags - moved, renamed + memcached migrations, etc.

Which issue(s) this PR fixes or relates to

Fixes #

Checklist

• Tests updated
• Documentation added
• CHANGELOG.md updated - the order of entries should be [CHANGE], [FEATURE], [ENHANCEMENT], [BUGFIX]

[pstibrany]

Looks good. < encoding as \u003c is fine, and "prefix" fields are coming from Cortex structs with doc:"hidden" tags. Missing ) in addresses field is also correct, and should be fixed in Cortex first.

[dimitarvdimitrov]

@pstibrany I've moved the GEM-specific removed options to gem.go. As far as I understand the rest of the comments are no longer a concern?

[pstibrany]

@pstibrany I've moved the GEM-specific removed options to gem.go. As far as I understand the rest of the comments are no longer a concern?

I resolved comments that are not a concern anymore. One remaining comment is a non-blocking nit, no need to block on that. One remaining comment was GEM-specific options 🤦