feat: field and block label improvements (experimental)

[BenHenning]

This also fills in more field labels (particularly for options) and adds example 'where am I?' shortcuts for team testing.

The basics

• I validated my changes

The details

Resolves

Fixes

Proposed Changes

Reason for Changes

Test Coverage

Documentation

Additional Information

[BenHenning]

This needs a bunch of explanation and work yet. It largely adds good naming for fields and drop-downs for all but the dynamic cases (since those are trickier and may need some additional work to make it possible).

It also splits field labels into type and values and largely keeps the type out of the block readout unless using new shortcuts.

Two new shortcuts:

• ctrl/command + shift + I: prints out a verbose readout of the current block
• ctrl/command + shift + P: prints out a verbose readout of the current block's parent

These are meant to provide initial possibilities as part of addressing RaspberryPiFoundation/blockly-keyboard-experimentation#764.

[BenHenning]

From feedback: ensure fields always read out their type + value (verbose) when focused.

[microbit-robert]

Could this not be abstract and have a default implementation that returned an empty string (or null)? I found myself going through and returning empty strings for quite a few custom fields in order to get up and running with this change, and having a default implementation would reduce the overhead.