Add ingester flag to customize message in limiter error messages

[kumanik]

What this PR does:
Adds an admin contact address flag to the ingester and uses it while printing error messages when hitting limits.

Which issue(s) this PR fixes:
Fixes #5452

Checklist

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

[kumanik]

@friedrichg Have a look

I was thinking of adding tests for checking contact details at-

cortex/pkg/ingester/limiter_test.go

Lines 504 to 508 in 21eb075

	limiter := NewLimiter(limits, ring, util.ShardingStrategyDefault, true, 3, false)
	actual := limiter.FormatError("user-1", errMaxSeriesPerUserLimitExceeded)
	assert.EqualError(t, actual, "per-user series limit of 100 exceeded, please contact administrator to raise it (local limit: 0 global limit: 100 actual local limit: 100)")

Or should I create a completely new test?

[friedrichg]

Thank you for your contribution!

You don't need to add any additional tests, just keep the current tests working.

[friedrichg]

Good job @kumanik , the only thing missing is a FEATURE in the CHANGELOG.

[kumanik]

It is done I suppose

[friedrichg]

Thank you!

[kumanik]

No, thank you. Really glad I could contribute. If there is anything to work on I would like to help.