Support multiple servers

[kazk]

Multiple servers can be registered by separating each with an option delimiter, and using the query parameter name to specify the command name on connection.
If no query parameter is present, the first one is started.

lsp-ws-proxy --listen 9999 --sync --remap \
    -- typescript-language-server --stdio \
    -- css-languageserver --stdio \
    -- html-languageserver --stdio

Choose the server with query parameter name when connecting:

• JS/TS: ws://localhost:9999 or ws://localhost:9999?name=typescript-language-server
• CSS: ws://localhost:9999?name=css-languageserver
• HTML: ws://localhost:9999?name=html-languageserver