Refactor the MQTT option and reconfigure flow

[jbouwh]

Breaking change

To reconfigure the MQTT broker settings users need to start a Reconfigure flow. When CONFIGURE is selected MQTT show a page "MQTT settings" with subscribe and publish tools. The Re-configure MQTT buttton will be replaced with a MQTT options page. The reconfiguration option will only be available from the MQTT Config Entry context menu.

Proposed change

Exclude the MQTT broker setup from the MQTT option flow and move the broker options to the config entry options.
Reconfiguration support was already added with: #132246

The special MQTT config entry page for the MQTT entry needs an update to clarify the MQTT options can be set from there.

Needs:

• Fix mqtt reconfigure flow #133315
• Frontend PR: Replace label on refactored MQTT option flow button frontend#23317

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New integration (thank you!)
• New feature (which adds functionality to an existing integration)
• Deprecation (breaking change to happen in the future)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue:
• Link to documentation pull request: Split MQTT options and reconfigure flow home-assistant.io#36397

Checklist

• The code change is tested and works locally.
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[home-assistant]

Hey there @emontnemery, @bdraco, mind taking a look at this pull request as it has been labeled with an integration (mqtt) you are listed as a code owner for? Thanks!

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[jbouwh]

Frontend PR was approved