feat(mixins): merge resources dashboards for ssd into one

[QuentinBisson]

What this PR does / why we need it:

Single Scalable deployment mixins were not showing the full resource usage as the backend pods were ignored.

This PR merges the existing read-resources and write resources dashboard into 1 for SSD and adds the backend resources. The idea was already communicated in with @cstyan in this PR #13023

Which issue(s) this PR fixes:
Fixes #

Special notes for your reviewer:

Checklist

• Reviewed the CONTRIBUTING.md guide (required)
• Documentation added
• Tests updated
• Title matches the required conventional commits format, see here
  • Note that Promtail is considered to be feature complete, and future development for logs collection will be in Grafana Alloy. As such, feat PRs are unlikely to be accepted unless a case can be made for the feature actually being a bug fix to existing behavior.
• 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

[QuentinBisson]

@cstyan or @MichelHollands I would love some inputs if you have the time of course

[cstyan]

@QuentinBisson am I understanding correctly, this should supersede your other PR #13023 ?

[QuentinBisson]

Yes and no 😅 because thé other PR also include the addition of a backend path in the Loki opérational dashboard so I will rename it later on :)

[cstyan]

@QuentinBisson need to merge in again after some of the other PRs have been merged

[QuentinBisson]

Should be good @cstyan :)

[QuentinBisson]

Hey @cstyan I regened the mixins on my hand but I have some weird layout on this one

I think I need to play with gridpos but I'm not sure how to do it so if you have some insight that would be awesome :)

[QuentinBisson]

Fix here #14178 😄