[webview_flutter] Copies app-facing implementation of webview_flutter from v4_webview (#6856)

* copy code from v4_webview

* version bump and readme update

* work towards better readme

* improvements

* more readme progress

* improvements

* fix main and update more readme

* excerpt changes and more 3.0 diffs

* cookie manager update

* remove packages from exclude list

* lint

* better range

* isForMainFrame

* load page after waiting for widget

* fix integration tests

* improve readme a bit

* collapse changelong. update platform-specific wording. include in excerpt tests

* use platform implementation packages

* include missing exports

* PR comments

* correct spelling

* interface dev dependency

* move other usage above migration

* remove interface classes
34 files changed
tree: 210a393fb9d9708dcde97b0cc1f8aaade5d7f2ef
  1. packages/