Update Javascript browser compat to new schema

[teoli2003]

Need PR #170 to land first

Will likely need a trivial rebase after it has landed.

[Elchi3]

This is not ready to be merged yet.

• Can't land without the MDN KumaScript macro being changed to work with the new schema. The Promise test pages on MDN make use of the data in the old schema.
• "desc": "Basic support" is present here as well. We might want to add a commit that removes these.
• Needs a rebase.

[Elchi3]

Also, I think the namespace should be "javascript.builtins.Promise" or "javascript.api.Promise".
There will be cases like:
"javascript.api.Function"
"javascript.operators.function"
"javascript.statements.function"

[Elchi3]

--> #206