Rack, Roda, Sinatra and other framework compatibility (when running on Opal and Node or alternative)

[janbiedermann]

... currently is lacking.

These patch sets show where things are missing in opal, or things go wrong:

For Roda: https://github.com/jeremyevans/roda/compare/master...janbiedermann:roda:master

For Rack https://github.com/janbiedermann/rack/commit/1dadea0f9813c2df94715052d2277af13f7d0c0c

For Sinatra, Rack-Protection: https://github.com/sinatra/sinatra/compare/main...janbiedermann:sinatra:main

For Mustermann: https://github.com/sinatra/mustermann/compare/main...janbiedermann:mustermann:main

For Rack-Session: https://github.com/rack/rack-session/compare/main...janbiedermann:rack-session:main

(Issue here to be referred by PRs which fix things)