chore: empty "main" in favor of v0.* branches

[antobinary]

What does this PR do?

• removed the source code (and most files) from main branch in favor of the (already pushed a minute ago) v.0.0.x and v0.1.x branches, similar to https://github.com/bigbluebutton/bigbluebutton-html-plugin-sdk

Closes Issue(s)

Closes # none

Motivation

• for new repos started from this template people can (should) fork ALL branches so their plugin is in best position to match the accepted pattern
• for existing plugin repos, pulling from the upstream template should now lead to fewer conflicts as we better manage the individual branches