feat!: cross-tab-copy-paste can copy more than just blocks

[maribethb]

The basics

• I validated my changes

The details

Resolves

Fixes #2565
Fixes #2562

Proposed Changes

Basically rewrote the plugin, perhaps easier to review this commit-wise.

• Converted plugin to typescript
• updated minimum version of Blockly to v12.1.0 because we need a new function only in that release
• updates all of the logic to be more similar to the logic in core, though with some bug fixes/improvements that were already in the plugin. notably, checks the type counts are allowed for blocks and handles event grouping. this work also enables workspace comments or other ICopyable items to be copied, not just blocks.
• allow customizing the local storage key
• use the Blockly.Msg values for clipboard shortcuts that now exist in core instead of hardcoded strings
• register the keys for shortcuts using .keyCodes property instead of manually calling addKeyMapping
• add workspace comments to the test page for easier testing.

Reason for Changes

Makes this plugin compatible with keyboard-navigation.

Test Coverage

Manual testing only because samples is not set up to use webdriver tests :(

Documentation

readme still looks good

Additional Information

[maribethb]

The test failures are with shadow-block-converter I guess as a result of updating to v12.1, so I'm going to fix that in a separate PR. Doesn't block review of this one :)

[maribethb]

note to self: remove formatting changes to colour-slider so it doesn't get a breaking change

[maribethb]

Tests should pass after #2574