Support additional upstream proxy connection formats

[reporter29]

This request addresses request #184 that I raised to supporting additional proxy formats. I tested my changes using my own proxy. The cases I tested are:

1. host
2. host:port
3. user:pass@host:port
4. user@host:port
5. user:pass@host
6. user@host
7. host:port:user:pass
8. host:port@user:pass
9. users:pass:host:port
10. user_12345,type_residential,session_123:pass:host.dev.com:1234 (complex valid)
11. user:pass:host:1080:extra (invalid)
12. user:pass:https://proxy.host.com:1234 (invalid)

Proxies in the format of 7-9 get saved to the rulesStore as format 3.

EDIT: Ran into some rebasing issues in my previous CR #185 and had to create a new pull request 😅