Allow configuring of tab titles

[felixhabib]

It is hard to distinguish between Playroom tabs when there is more than one in the same window.

This change:

• Adds a "Title" section in the settings pane which allows you to customise the tab title.
• Saves Titles in the URL.
• Updates spacing scale logic.
• Removes dividers in all menus for consistent visual treatment.

For example

[changeset-bot[bot]]

🦋 Changeset detected

Latest commit: 831e1f3b252425ba76a8821bc9b172c3b870dd5a

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

| Name | Type | | -------- | ----- | | playroom | Minor |

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