Improve middleware extrusion path parsing

[pjenvey]

We now manually parse url paths for the:

• HawkIdentifier uid
• bso parameter
• collection parameter

We still have a TODO to improve the parsing. It could at the very least be more strict by checking for a leading /1.5/. Maybe there are other additions

[crisadamo]

Hello guys, I would like to contribute to the project. Was thinking if this is a good task to start?

[pjenvey]

Thanks for your interest @crisadamo

Our team is actively focusing the SpannerDb backend, so there's a fair amount of changes happening in src/db/spanner. I'd stay out of there to avoid conflicts.

I think a good place to start would be issue #174, I've updated the issue with some more information. I'd recommend starting with some smaller changes (say src/web or just middlware.rs to start with).

#53 is also another good issue to start with, and could be applied to solely the mysql backend and ported to Spanner later. Though we may be tackling that one ourselves sooner rather than later

[crisadamo]

Thanks @pjenvey I'll take a look at #174 and probably will move to #53 afterwards