Extract component handlers packages out of monorepo

Currently

We have:

• frint-component-handlers
• frint-router-component-handlers

Which are used respectively by:

• frint-react
• frint-router-react

We did it that way to enable us to create other packages integrating with various rendering libraries (like Preact, Vue, and others).

Proposal

We haven't done any further maintenance of other integration packages, besides the one for React which exists in the monorepo.

I suggest moving the handler packages out of the monorepo, so other integration packages can still use them.

But the React integration packages that we have in the monorepo don't need to use them any more to make lives of core maintainers easier.