feat(input): add legacy and modern template rendering

[liamdebeasi]

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)
  • Some docs updates need to be made in the ionic-docs repo, in a separate PR. See the contributing guide for details.
• 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

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?

Issue URL: N/A internal ticket

This is one PR of several for the FW-2591 feature

What is the new behavior?

• Moved legacy input tests to the legacy directory. Note: Screenshot contents should not be modified.
• Added a single basic test file. These tests will be filled out as functionality is added.
• When the legacy template is rendered, a deprecation warning will be logged with information on how to migrate.
  Note: Deprecation messages regarding using ion-input inside of ion-item or using the shape/fill props on ion-item will be handled in a separate PR.
• Added a stubbed template for the modern input template.

Legacy Form Controller
This is a temporary controller that was added to abstract away the logic of when to render a legacy vs modern component template. All form controls should have the same criteria, so this can be used for each form component.

This should be removed when the legacy syntax is removed.

Does this introduce a breaking change?

• Yes
• No

Other information