Convert this package to a federated plugin

[TekExplorer]

I would like to use the linux implementation of this package without the macos or windows implementations.

inapp_webview does not have linux support, and the combination of flutter_webview and webview_windows also excludes linux.

flutter_linux_webview does not support js channels

Including this package causes issues for builds, because the plugin includes code and build hooks that are completely unnecessary for those platforms.

therefore, please split the package up into federated packages, similar to other plugins like inapp_webview.