[MM-61915] feat: support configurable scheme for serverURL

[fmartingr]

Summary

Added a new ServerScheme configuration paramater for the deployer to allow using https on custom deployments, automatically setting up wss if that is used.

Ticket Link

https://mattermost.atlassian.net/browse/MM-61915

[agarciamontoro]

Oh, neat, thank you! A nice addition here would be to centralize building the scheme in a util function so that we can refactor out all of those t.config.ServerScheme + "://". Thoughts?

[streamer45]

Am I the only one who thinks this is getting slightly confusing?

We already have two settings to override URLs in slightly different ways, and now we are adding a third to control the scheme portion. I think that eventually we'll need to take a step back and try to simplify some of it because we are starting to tweak things for any little new use case we find. @agarciamontoro Thoughts?

Also, what happens if either SiteURL or ServerURL already have a scheme set?

[fmartingr]

Am I the only one who thinks this is getting slightly confusing?

No 😬 It already was, honestly, based on the logic around the code regarding the URLs, the proxy, etc.

We already have two settings to override URLs in slightly different ways, and now we are adding a third to control the scheme portion. I think that eventually we'll need to take a step back and try to simplify some of it because we are starting to tweak things for any little new use case we find. @agarciamontoro Thoughts?

The problem here is what to use in what places. Honestly I would just use a complete setting (a complete URL) as the URL the clients should connect to, that being a node, a proxy, a load balancer... and leaving it empty would try to guess what to use from the configuration.

Also, what happens if either SiteURL or ServerURL already have a scheme set?

it won't work since the code prepends the scheme (both before and after this change)

I will let you discuss this a bit internally before making more changes to the PR.