tests(controls): Change API from controls to controller

[karangattu]

Fixes #1450

We wanted to make sure the test templates can be run by the user instead of an error.
So we want to users to import controller as shown below

from shiny.playwright import controller

def test_app(page, local_app):
    # Set up controllers here
    btn = controller.InputButton(page, "btn")`
    ....

This is a change from the current implementation

from shiny.playwright.controls import InputButton
def test_app(page, local_app):
    # Set up controllers here
    btn = InputButton(page, "btn")`
    ....

This change modifies all playwright tests in line with this API change

[schloerke]

Q: Was shiny playwright testing exposed in v0.10?

If it was exposed in v0.10:

• We need a deprecation entry in the changelog.
• We also need a file at shiny.playwright.controls that if loaded will display a deprecation warning.
• This file should reexport all of the controllers objects.

[schloerke]

A: It was not in v0.10.

If it was not exposed in v0.10:

• Move the changelog entry up from the v0.10 to latest changes.
• Expand a little upon what is in shiny.playwright

Both:

• Add changelog entry for shiny add test

[schloerke]

@karangattu Ready to merge when you are