Improve Review Apps cleanup when previous deployment failed by only issuing an `helm delete` command

Closes #63639 and #62161

See merge request gitlab-org/gitlab-ce!28661

Pass branch name to the CNG pipeline for stable branches

See merge request gitlab-org/gitlab-ce!29617

Signed-off-by: Rémy Coutable <remy@rymai.me>

Signed-off-by: Rémy Coutable <remy@rymai.me>

This includes several changes:
  - Rename memory-static to generate-gems-size-metrics-static
  - Rename memory-static-objects to generate-gems-memory-metrics-static
  - Change generate-gems-size-metrics-static interface. The script now
    expect `bundle exec derailed bundle:mem` output as its input. The
    script output to stdout, or stderr for error message.
  - Change generate-gems-memory-metrics-static interface. The script now
    expect `bundle exec derailed bundle:objects` output as its input.
    The script output to stdout, or stderr for error message.
  - Generate gem size metrics. Script generate-gems-size-metrics-static
    extract each gem size from `bundle exec derailed bundle:mem` output.
    Save output to metrics file in format: 'gem_size_mb{name="zip"} 0.5'

Signed-off-by: Rémy Coutable <remy@rymai.me>

Two static memory benchmarks will be included in our CI pipeline. It
will load gems from the Gemfile and check the amount of RAM consumed
as well as the number of objects allocated and retained.
Aggregated values will be included as 'metrics' into MRs while full
reports will be downloadable as job artifacts.

Disable hooks by setting an ENV var

See merge request gitlab-org/gitlab-ce!29672

Prior to this change, the hooks directory got cleared. That works, but
is not the way to go about it as there's a better way. Setting the env
var this commits sets.