feature: launch namecoin

[ethicnology]

Intent

Launch a Namecoin client such as Namecoin Core if it's installed when Zeronet launches.

NamecoinUtils.py give a set of functions.

• is_namecoin_installed check if a .namecoin folder exists in the (linux) user directory.
• is_namecoin_running check if a running process contain the string namecoin.
• check_namecoin_rpc_conf ensures that the necessary variables are set.
• start_namecoin execute a subprocess of namecoind
• kill_namecoin kill the given pid process

Add del function to SiteManagerPlugin.py

• del function kill the Namecoin client if it was launched by ZeroNet on ZeroNet shuts down.

Process

• self.config is initiated with CLI args, if provided
• is namecoin installed ?
  • is namecoin running ?
    • if conf is not set, check for namecoin rpc conf in namecoin.conf
      • if there is no namecoin.conf raise missing parameters error.
  • start namecoind (if path is given)

Limitations

For the time being, it only works on linux, we can upgrade it for windows and macos users later

Nota bene

I pushed with debug logs to make it easier for you to test, i will remove them before merging, if you agree