Register editor style.css and create block patterns

[crftwrk]

Closes #55
Closes #442

https://youtu.be/GrLLuyhJP1g

This is a good one addressed to v6 stable. Predefined Bootstrap components can now be added without using a plugin.

• Registers compiled main.css as editor-style.css. Bootstrap styles are now applied to the GB editor
• Created some patterns like cols and buttons. Click the + button on top left to insert a new block > Patterns > Bootscore > choose block pattern

Edit Needs a theme.json remove inner div in group

• Alerts
• Buttons
• Cards
• Jumbotron
• Container
• Sections
• Heroes