Pull in other plugins (can be individually or all at once) #7764

This is part of the monorepo project.

• Copy plugins from blockly-samples into blockly
• Update versions to respect locked versioning, and update dependencies to use workspace-style notation
  • @maribethb to add more detail here
• Test that npm install, npm build, and npm test work
  • From the root of the monorepo
  • From inside each plugin's directory
• Reenable "Elements focused" unit test in plugins/typed-variable-modal (was temporarily disabled in googlel/blockly-samples#2228).

Depending on the amount of work needed, this may be done on single plugins or on multiple plugins as a batch.