Rearchitect tcconfig

[thombashi]

tcconfig 1.0.0 or newer includes several breaking changes:

• [ ] Current tcset/tcshow/tcdel commands will become a single command
  • tcxxx commands will be sub-commands of the new command
    • command aliases may keep left for backward compatibility
  • to reduce the file size of binary packages
  • to be more easily add sub-commands
  • [ ] needs to decide the command name
    • candidate: tcconfig, tcc, etc.
• [ ] Change import/export functionality/file-format
• [ ] subcommands:
  • set (equivalent to tcset)
  • show (equivalent to tcshow)
  • del (equivalent to tcdel)
  • version
  • server (receive commands from clients)
  • client (sent commands from servers)
  • import
  • export
• [ ] Add type annotations