fix: allow to configure http_config for ruler

[sebhoss]

What this PR does / why we need it:

This allows to configure http_config in the ruler section.

Which issue(s) this PR fixes:
Fixes #12112

Special notes for your reviewer:

Checklist

• Reviewed the CONTRIBUTING.md guide (required)
• Documentation added
• Tests updated
• CHANGELOG.md updated
  • If the change is worth mentioning in the release notes, add add-to-release-notes label
• Changes that require user attention or interaction to upgrade are documented in docs/sources/setup/upgrade/_index.md
• For Helm chart changes bump the Helm chart version in production/helm/loki/Chart.yaml and update production/helm/loki/CHANGELOG.md and production/helm/loki/README.md. Example PR
• If the change is deprecating or removing a configuration option, update the deprecated-config.yaml and deleted-config.yaml files respectively in the tools/deprecated-config-checker directory. Example PR

[CLAassistant]

All committers have signed the CLA.

[JStickler]

@sebhoss Could you please also update the Helm chart version in the README and resolve conflicts for the CHANGELOG and Chart?

[sebhoss]

@JStickler yep done - thanks! .. and sorry for closing/re-opening this PR .. I'm kinda bad with buttons today 😅

[sebhoss]

Rebased on latest main

[sebhoss]

@MichelHollands thanks! I just pushed a new change to fix the commit message. Since the original ticket was classified as bug I used 'fix' instead of 'feat' here though..