Add "capitalize" option to hui-timestamp-display

[spacegaier]

Breaking change

Proposed change

Similar to PR #9481 for <hui-timestamp-display> plus add a few missing "capitalize" attributes to <ha-relative-time> for consistency.

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Type of change

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

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Additional information

• This PR fixes or closes issue: fixes Timestamps's state first letter not capitalized #10279
• This PR is related to issue or discussion:
• Link to documentation pull request:

Checklist

• The code change is tested and works locally.
• There is no commented out code in this PR.
• Tests have been added to verify that the new code works.

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated for www.home-assistant.io