Feature Request: Allow proxy settings per server

[zdzielinski]

Some IRC servers for certain purposes require (or request) that users not use a proxy connection when connecting.

Regardless of the intended purpose, the ability to set proxy settings per server would prove a useful feature.

Right now, the only way to set proxy settings is globally via the [proxy] config section.

One method to achieve this could be by allowing proxy configuration to mimick the global [proxy] section within a TOML subsection.

IE:

[servers.example]
...
[servers.example.proxy]
... config here

[oooo-ps]

I've just implemented it for myself. See PR: https://github.com/squidowl/halloy/pull/1318