Fix --base-url improper path and protocol handling using zola serve

[jamwil]

Correctly parse the protocol and path from the base url, and differentiate between the bound interface and the base URL when using zola serve.

Closes #2170.

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Code changes

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[jamwil]

I'm marking this as Ready for Review.

The discussion in #2170 can be split into two separate features—the first being to properly parse the base_url so that zola serve works at various endpoints, including https endpoints. I believe this PR handles that use case without any changes to existing documentation.

The second feature requested in #2170 is to allow arbitrary paths while serving the content from a static /public directory (or wherever it is configured). This ventures into url_rewriting territory and, as far as I can tell, would require patching the make_service block in serve.rs.

I'm going to open this up to Allow edits by maintainers if anyone wants to delve further into it, and I'm open to guidance from someone that understands the codebase better than I do, but I think this is a suitable patch to tackle part of the issue as is.

See additional comment.

[jamwil]

I worked through the mounting problem. We should be able to serve at any arbitrary endpoint, including subpaths. This should close #2170.

[jamwil]

Looks like the changes I made to support paths introduced a regression for the https change. I'm investigating.

[jamwil]

Fixed the regression here. This should work as stated on the tin.

[Keats]

Can you cherry pick the commits on a rebased next branch?

[jamwil]

Can you cherry pick the commits on a rebased next branch?

Yep, working on it. Some signatures have changed so it's a bit of an involved merge.

[jamwil]

@clarfonthey This PR has a lot of overlap with the work you did in January. Just wanted to give you a heads up so you can verify that it doesn't introduce any regressions to your work. It was a bit of a delicate merge.

[clarfonthey]

Thanks for the heads up @jamwil; any work I haven't merged is probably going to be redone anyway, so, I'm not worried about conflicts.

[jamwil]

@Keats Is there anything outstanding that we need to address?