## Description

This improves defaults generation with logging, stats, and token validation. 

This PR includes these changes:
* introduce `TokenLogger`, with a verbose mode
  * prints versions and tokens usage to the console
  * outputs `generated/used_tokens.csv`, a list of all used tokens, for use by Google
* find token files in `data` automatically
* hide tokens `Map`
  * tokens can be obtained using existing resolvers (e.g. `color`, `shape`), or directly through `getToken`.
  * tokens can be checked for existence with `tokenAvailable`
* remove version from template, since the tokens are aggregated and multiple versions are possible (as is the case currently), it does not make sense to attribute a single version
* improve documentation

## Related Issues
 - Fixes https://github.com/flutter/flutter/issues/122602

## Tests
 - Added tests for `TokenLogger`
 - Regenerated tokens, no-op except version removal

## Future work
A future PR should replace or remove the following invalid tokens usages

<img width="578" alt="image" src="https://github.com/flutter/flutter/assets/6655696/b6f9e5a7-523f-4f72-94f9-1b0bf4cc9f00">

Fixes #122250. This PR is to make sure all the MaterialStateProperty defaults are able to correctly resolve different states. 
* When a widget is pressed, it is also hovered, so we need to put the `MaterialState.pressed` check before `MaterialState.hovered`. 
* When a widget is focused, the widget should still be able to be hovered, so we should check `MaterialState.hovered` before `MaterialState.focused`.
* There are also cases like in _InputDecoratorDefaultsM3, the `MaterialState.disabled` should be checked before `MaterialState.error`.

 the order should be disabled, (error), pressed, hovered, focused.

* Added support for surfaceTintColor and shadowColor to the Dialog widgets.
* Updated the defaults for Material.shadowColor and Material.surfaceTint to allow turning off the features with a transparent color.
* Added support for shadowColor and surfaceTintColor for Drawer widget.

This reverts commit 79013b2b.

* Revert "Revert "Set `IconButton.visualDensity` default to `VisualDensity.standard` (#109349)" (#109421)"
Co-authored-by: Qun Cheng <quncheng@google.com>

This reverts commit 3070baf1.

* Set IconButton's visualDensity to standard
Co-authored-by: Qun Cheng <quncheng@google.com>

* Created IconButtonTheme and apply it to IconButton

Refactor gen_defaults to support multiple generated code blocks in the same file independently. (#107278)

* Added standard IconButton for M3 with new ButtonStyle field

* Added IconButton examples for standard, filled, filled_tonal, and outlined types
Co-authored-by: Qun Cheng <quncheng@google.com>