Wrong scope of public api's dependencies

[rosolko]

Describe the bug
All public available api's dependencies should be placed in api scope

Note: If I want to implement ResponseFilter I should manually add io.netty:netty-codec:4.1.43.Final library to my project. And it can produce library version incompatibility.

To Reproduce
Steps to reproduce the behavior:

1. Try to implement ResponseFilter

Expected behavior
io.netty.handler.codec.http.HttpResponse is available for use

Screenshots
Class isn't in Compile scope. By default it has Runtime scope.

Please complete the following information:

• OS: macOS 10.15.1 (19B88)

Additional context
To fix this issue place all public available api and dependencies in api scope instead of implementation

[rosolko]

Also there is a problem with littleproxy. Without directly adding xyz.rogfam:littleproxy:2.0.0-beta-5 to dependencies I've got an error about missing HttpFiltersSource class during BrowserUpProxyServer extends.

[ericbeland]

We are open to pull requests if you have a fix. We're in the midst of some other implementations at the moment.