[1.x] Added configuration of gx-it-proxy to support path-based proxying

[natefoo]

Supersedes the 0.x-based #96.

Only adds --proxyPathPrefix if the Galaxy config option is set, which by my reading of galaxyproject/gx-it-proxy#14 should be valid, but correct me if I'm wrong @sveinugu.

[sveinugu]

Hi @natefoo. Sorry for the very late review on this.

We (@morj-uio and myself) have now reviewed your merge of our PR and have added some comments in the code. We had to spend some time to remember the details, but it is now relatively clear to us that there is no reason to not always set --proxyPathPrefix, as the path-based IT solution should really be the fallback when domain-based ITs are not available (i.e. when there is no wildcard DNS) and not the other way around. For now, the use of path-based IT mapping can be regulated on a tool-by-tool basis (by setting requires_domain to False for path-based) until we are confident that this works as intended. In any case, the interactivetools_base_path is not the correct config to check, as the default is /.

[natefoo]

@sveinugu ok, I think this does it as discussed, can you confirm this looks right to you?

[sveinugu]

I think one of the tests is checking too little. Other than that: LGTM

[sveinugu]

I believe tests are failing due to lack of version bump in gx-it-proxy: galaxyproject/gx-it-proxy#16. Bumped versions should be harmonized across galaxy, gravity, and gx-it-proxy.

[natefoo]

Ok, the new version of gx-it-proxy is published, but the tests are now failing due (at least in part) to galaxyproject/galaxy#15765, so we can rerun once that is fixed.