Picked up from #22498, originally by @jugyo

Fixes https://github.com/flutter/flutter/issues/25703

We decided that redefining the default for templates was premature. We're going to go back to having "module" in experimental land again, and we'll try again when we have the feature set fully baked.

This keeps the writing of the .metadata files, and writing the template type to them, because that was a good improvement, and there are still a bunch of added tests that improve our coverage.

This renames the "module" template to the "application" template, and makes "application" the default. The existing "app" template is now deprecated.

flutter create also now recognizes the type of project in an existing directory, and is able to recreate it without having the template type explicitly specified (although you can still do that). It does this now by first looking in the .metadata file for the new project_type field, and if it doesn't find that, then it looks at the directory structure. Also, the .metadata file is now overwritten even on an existing directory so that 1) the project_type can be added to legacy projects, and 2) the version of Flutter that updated the project last is updated.

I also cleaned up a bunch of things in create_test.dart, added many more tests, and added an example test to the test/ directory in the generated output of the application template.

Fixes #22530
Fixes #22344

* Prototype

* Fix paths to Flutter library resources

* Invoke pod install as necessary for materialized modules

* Add devicelab test for module use on iOS

* Remove debug output

* Rebase, reame materialize editable

* Add devicelab test editable iOS host app

* Removed add2app test section

Renamed 'flutter materialize' to 'flutter make-host-app-editable'. The iOS version is still incomplete and will therefore require additional renaming. (#21771) (#22006)

* enable lint unnecessary_new

* fix tests

* fix tests

* fix tests

* Upgrade everything except matcher.
* Roll matcher (and test)
* Adjust tests that depend on flutter:test directly to depend on a shim
* Require use of package:test shim and remove other references to package:test

With a fix of a path being printed relative instead of absolute.

This reverts commit 57d78cc7.

Add iOS module template

This will enable integration of flutter-views into existing iOS project.

This reverts commit 8be198d8 that broke the build.

Add iOS module template

This will enable integration of flutter-views into existing iOS project.

Uses the `version` property from the `pubspec.yaml` file to set the corresponding fields in the `local.properties` file respectively in the `Generated.xcconfig` file.

The `--build-name` and `--build-number` options have changed. Now they trump the `version` property from the `pubspec.yaml` file.

If the `version` property is not set and the  `--build-name` and `--build-number` options are not provided, the build command will not change the `local.properties` / `Generated.xcconfig` file.

Package projects were erroneously being treated as apps

This reverts commit b3e4976c.