HTTP Server to manage klips for browser runtime

[mpetuska]

Since js tests running on the browser runtime do not have access to fs module, an alternative way to write to files is required.

This can be solved by implementing a simple HTTP server managed by gradle and tied to jsBrowserTest tasks lifecycle, that would manage klip files via fetch API.

This should be toggled by a new flag injected by the compiler (defaults to true only for js sourceSets). Alternatively, this could be detected implicitly in klip-core and only enable itself if browser runtime is detected.