Consolidate fedRAMP sla and s1/s2 slo label names

What does this MR do and why?

Describe in detail what your merge request does and why.

closes SLO label and automation consolidation (#1236 - closed)

We are consolidating label names as described in gitlab-org/gitlab#388707 (comment 1267735190)

The MR requires the following labels to be renamed at the same time:

• rename ~"FedRAMP Milestone::Vuln Remediation" to FedRAMP::Vulnerability
• rename ~"Remediation SLO::Near Breach" to SLA::Near Breach
• rename ~"Remediation SLO::Breach" to SLA::Breached
• rename ~"missed-SLO" to SLO::Missed
• rename ~"approaching-SLO" to SLO::Near Miss

cc @dsatcher @vincywilson

Expected impact & dry-runs

These are strongly recommended to assist reviewers and reduce the time to merge your change.

See https://gitlab.com/gitlab-org/quality/triage-ops/-/tree/master/doc/scheduled#testing-with-a-dry-run on how to perform dry-runs.

Action items

• If adding environment variables for reactive processors, update config/triage-web.yaml and .gitlab/ci/triage-web.yml
• (If applicable) Add documentation to the handbook pages for Triage Operations =>
• (If applicable) Identify the affected groups and how to communicate to them:
  • /cc @person_or_group =>
  • Relevant Slack channels =>
  • Engineering week-in-review