Server: Create API endpoints to CRUD blocks

[IkeHunter]

• Use dummy block data for now

Docs: https://developers.google.com/blockly/guides/create-custom-blocks/define-blocks#json

[jonaswood01]

• Use dummy block data for now
• Docs: https://developers.google.com/blockly/guides/create-custom-blocks/define-blocks#json

For block endpoint:

• Create
• Read
• Update
• Delete