feat(control server authentication): add basic http auth

[joejose97]

• Add basic http auth to vpn/settings & openvpn/settings routes.
• Get username and password from environment variables.
• Sets a default username and password.

Partly fixes #2238

@qdm12 , please provide feedback.
Do we need a default username and password.
I have added basic auth only for the /settings route so that breakage with existing users are minimal.

Edit:
Original PR is updated to use the new auth middleware. Above points are no longer valid.
See #2238 , #2434

[qdm12]

Please see and reply to #2238 (comment) 🙏
My apologies for not doing this earlier, as @ezekieldas pointed out, this turns out to be rather urgent to fix/do something about it (changed the priority of the issue to urgent)!

[qdm12]

Can you point your PR towards the branch auth-middleware-2238 and inspire from #2437 to implement basic auth with the new 'auth code infrastructure' in place? 🙏 Thanks!

[joejose97]

I've updated to use the auth middleware.
Sorry for the delay.

[qdm12]

I've updated to use the auth middleware

Awesome 💯 ❤️
FYI I rebased your branch + pushed a small commit to simplify code a bit

Sorry for the delay.

Please, no pressure at all 😸