Fix base URI not included in generated OpenID Connect URLs (#1524)

[hmoffatt]

OpenID Connect login does not work when the base URI includes a path component. This PR fixes this.

[hmoffatt]

HI @fiftin it would be great if you can review this, it is a relatively simple change but OIDC + sub-path on the URL does not work without it. Thanks.

[tboerger]

Since there is the WebHost options this makes sense.

[ChristianCiach]

Since these changes have been approved, could this PR be merged, soon? Currently, using OpenID-Connect with SEMAPHORE_WEB_ROOT is broken.

[stuntguy3000]

Any movement on this PR? I'd like to call out the documentation suggests doing this for those who run reverse proxies.

https://docs.semui.co/administration-guide/configuration#public-url

After two days of OIDC troubleshooting, coming across this was a relief.

[veshus]

Huh, is anybody here?

[hmoffatt]

I have rebased this against the current develop, @fiftin perhaps you have a chance to have a look?
I have my Semaphore hosted at https://domain.com/semaphore and it is working for me with this change.

[fiftin]

Hi @hmoffatt , @tboerger sorry, I missed this PR.

[fiftin]

Did you test it?

[hmoffatt]

Did you test it?

Yes I am running it for nearly a year now with web_host set to https://xyz.com/semaphore .

[fiftin]

Thank you! Merging.

[hmoffatt]

Hey @fiftin thanks but I don't see the commits on develop ?