[flutter_tools][web] Add support for web app manifests and arbitrary resource files (from web/) (#48316)

Step 1 of 2: Warn about Flutter's FloatingActionButton dependency on ThemeData accent properties (#48435)

This simplifies the diagnostic output for the Shortcuts widget so that if a debugLabel is supplied, then that is printed instead of the full list of shortcut keys in the map. Also, the output of the shortcut map is simplified to have the list of keys presented in more readable text.

* Implement reverseTransitionDuration in TransitionRoute

Document reasoning for why CustomMultiChildLayout size can't depend on children and how to do it (#48451)

Moves the checks that projects have been configured for desktop to a lower level, where they will cover more codepaths (e.g., 'run'), and improves them to check for native build projects, rather than just directories, to catch cases where the directory exists (e.g., due to accidental creation of generated files).

Also adds links to the error messages pointing to instructions on adding desktop support to a project.

Fixes #47145

[flutter_tool] Refactor Logger and Terminal to (mostly) no longer depend directly on context (#47269)

* Added property for expanded padding of expansion panel for solving #24071

* #24071: Renamed default const name for being more descriptive

* #24071: Improved comment of property expandedPadding

* #24071: Improved test by expanding the expansion panel by header tap + precise assertion

* #24071: Renamed property to be more descriptive

* #24071: Adjusted property comment and added missing trailing commas

* #24071: Improved test by checking real exact header size

* #24071: Added test for default header padding

* #24071: Improved comment of expandedHeaderPadding + code style adjustments

* #24071: Added missing trailing comma

This adds CatmullRomCurve animation curve, and a CatmullRomSpline, which is what it uses to do interpolation.

This allows us to create animation curves which can smoothly interpolate the values given to the curve.

Since I've introduced a 2D spline curve, I also created a Curve2D base class for such parametric curves.

This is follow-up to https://github.com/flutter/flutter/commit/ee7a37f1d3f12ca815d755a557f16765942897a4.

Revert "Document reasoning for why CustomMultiChildLayout size can't depend on children and how to do it (#47797)" (#48369)

This reverts commit de2514c0 as it breaks analyze-linux and web_tests-0-linux checks.

Document reasoning for why CustomMultiChildLayout size can't depend on children and how to do it (#47797)

This reverts commit 866fa64d.

* Reword flutter run help screen.

* As per Hixie request, added Efthymios Sarmpanis to the AUTHORS file

* fix test
Co-authored-by: Efthymis Sarmpanis <e.sarbanis@gmail.com>