WIP: Dynamic module loading

[filrak]

Related issues

Short description and why it's useful

Now VSModules can be seamlesly lazy loaded. The dynamic loading is based on actions.
How it works:

• somewhere in the theme we are dispatching action e.g wishlist/load
• VS is checking if module wishlist is registered
• if it is it's just dispatching the action (normal behavior)
• if it's not it lazy loads module, registers it and dispatches the action

With this approach VS modules can be lazily loaded seamlessly and users don''t need to take care of the registration themselves. They just need to register module as a lazy one in modules.index.ts and vs will take care of lazy loading it in a right moment. This will end up with HUGE reduction of bundle size.

To add

• dynamic loading based on getters.

[pkarw]

This is serious thing! I’m wondering about the performance results afterwards!
How to add the modules to prefetching list (for the offline mode)?

Great job @filrak! The modules proved its value once again

[filrak]

@pkarw this feature needs to be finished and polished tho so this PR will not be merged into 1.7

[pkarw]

@filrak OK