Idea: Support HTTP paths via OS_AUTH_URL-based http paths as well

[jtratner]

For certain users, it might be easier to just stick with HTTP paths rather than using our swift:// based paths. Especially if something is generally open via http, it's pretty useful to be able to, e.g., pass the same URL to samtools and to stor and to pandas, without needing to convert it.

Let's say we have something like:

https://swift.counsyl.com/v1/AUTH_myaccount/container/someobject

then we could store that as a SwiftHTTPPath (subclass of SwiftPath), but that still returns same thing for account / container / resource, but just has slightly different internal representation and return value for str.

Just thinking about it for now, but might simplify things in CLI.

There is some strangeness because currently we define different swift endpoints by region because we don't have geographic DNS (e.g., OS_AUTH_URL in some places is swift-region1.counsyl.com and in other places is swift.counsyl.com) but it might be easier for playing around with things. (plus we'd probably want to persist everything as swift paths instead).

Thoughts @kyleabeauchamp @kristjaneerik @pkaleta @krhaas @wesleykendall ?

[kristjaneerik]

I'm in favor!
I added an --url argument to stor ls/list/listdir in #34 and kind of guessed how to make the HTTPS URL in https://github.com/counsyl/stor/pull/34/files#diff-8741605745cec42f16e58241af303c8dR510 using auth_url, but it would be good to have a .to_http_path() method on SwiftPath or a .url attribute to get the URL in a clean way.