Make it possible to provide custom TCP options

[mentels]

Such work has already been made in:

• tcp_options branch
• temporary_escalus_tcp_update branch (it even made it the master branch)

However I see a few issues here:

• we allow to set the mode: {mode, Mode :: binary | list} - but this is wrong as escalus expect the received data to be binary (e.g. the calls erlang:byte_size/1 on it here
• if would say the same is for active
• we disable Nagle's algorithm by default {nodelay, true} but have we measured it helps us?
• we set {reuseaddr, true} but we already know that setting this to true prevents us from squeezing ~50K users from one Amoc node

IMO that is to be fixed.

cc @erszcz, @michalwski @bszaf

[mentels]

OK, nodelay has been there in the first place so I guess someone had measured that is helps.