fix(rules): handle apiserver normalized buckets

[skl]

This PR takes the work and feedback from #965 and #1006 and brings it into a single PR which:

• Updates the API Server availability and burn-rate recording rules to support both Prometheus v2 {le="1"} and v3 {le="1.0"} histogram bucket formats. This is achieved through the use of regex matchers to make the decimal part optional.
• Also updates some matchers which were missed in Fix: Handle float apiserver buckets #965
• N.B. double-double-escaped regex required (once for jsonnent and once for Prometheus).

I did an ad-hoc benchmark of query latency difference for the apiserver_request:availability30d recording rule on a fleet of clusters and saw no significant differences when using the regex matchers in this PR.

Supersedes #965 #1006
Fixes #1005

[SuperQ]

LGTM, Thanks!