4054 [camera] android-rework part 8: Supporting modules for final implementation (cla: yes, waiting for tree to go green, p: camera, platform-android)

4055 [in_app_purchase_android] add payment proxy (cla: yes, waiting for tree to go green, p: in_app_purchase, platform-android)

4061 [ci] Add release github action (cla: yes, waiting for tree to go green)

4062 [integration_test] Update README installation instructions (cla: yes, waiting for tree to go green, p: integration_test)

4064 [flutter_plugin_tool] Refactor createFakePlugin (cla: yes, waiting for tree to go green)

4069 [image_picker] remove unused imports from example (cla: yes, waiting for tree to go green, p: image_picker)