[Vue] Tree-shakeable controllers from @ionic/core

[michaeltintiuc]

Pull request checklist

Please check if your PR fulfills the following requirements:

• Tests for the changes have been added (for bug fixes / features)
• Docs have been reviewed and added / updated if needed (for bug fixes / features)
• Build (npm run build) was run locally and any changes were pushed
• Lint (npm run lint) has passed locally and any fixes were made for failures

Pull request type

Initial introduction of tree-shakeable controllers from @ionic/core as a replacement to proxy based ones.

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

What is the current behavior?

Currently the controllers are accessed via a global Vue.$ionic object which is not tree-shakeable.

What is the new behavior?

The previous behavior is kept and a deprecation warning is added.
It is now also possible to import controllers directly via import { modalController } from '@ionic/vue'

Does this introduce a breaking change?

• Yes
• No

[liamdebeasi]

Thanks for the PR! This is resolved in Ionic Vue for Vue 3.