feat(loki-mixin): allow disabling thanos dashboard and fix dashboard's file name

[WhiteDiamondz]

What this PR does / why we need it:

This PR allows disabling the thanos dashboard if not used and fixes it's unconventional json name.

Which issue(s) this PR fixes:

Trying to apply the generated dashboard's file would give the following error:

one or more objects failed to apply, reason: GrafanaDashboard.grafana.integreatly.org "loki_thanos_object_storage" is invalid: metadata.name: Invalid value: "loki_thanos_object_storage": a lowercase RFC 1123 subdomain must consist of lower case alphanumeric characters, '-' or '.', and must start and end with an alphanumeric character (e.g. 'example.com', regex used for validation is '[a-z0-9]([-a-z0-9]*[a-z0-9])?(\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*').

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
• 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

[WhiteDiamondz]

Hey @fcjack !

Sorry for tagging you, I saw you had reviewed a few PRs and the original one that had added this dashboard and I was hoping to get your thoughts on this change.

Thanks for your time and contribution ! 🙏

[fcjack]

LGTM! Thanks for the contribution

[WhiteDiamondz]

LGTM! Thanks for the contribution

Great thanks for the review @fcjack ! I see that some workflows are waiting for aproval, as this is my first time contributing in this specific repository is there anything on my end that needs to be done ?

[JStickler]

as this is my first time contributing in this specific repository is there anything on my end that needs to be done ?

@WhiteDiamondz I see that you've signed the CLA, so you're good to go. I'll merge this as soon as the checks pass.