Added range query support to write-read-series-test in mimir-continuous-test tool

[pracucci]

What this PR does

In this PR I'm adding support to query back written series (using range query) to write-read-series-test in mimir-continuous-test tool.

At each interval, after writing series the tool query back the time range successfully written until that point in time. The queried time ranges are:

• Last 1h
• Last 24h
• From last 23h to last 24h
• Random time range (up until the configured max query age)

Out of the scope of this PR (will be done in follow up PRs):

• Test instant query
• Query results cache disabled too
• Find the previously written samples at startup, so that it can continue write and read after a restart
• CHANGELOG
• Doc

Which issue(s) this PR fixes or relates to

N/A

Checklist

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

[pstibrany]

I didn't check all the unit tests thoroughly, but series testing logic seems solid. Nice work.