Previously just ipfs://<cid> and ipns://<cid> was supported, which is
too strict for some usecases.
This patch allows paths and query arguments to be used too.
Making this work according to normal http semantics:
ipfs://<cid>/foo/bar?key=val
ipns://<cid>/foo/bar?key=val
The gateway url support is changed.
It now only supports gateways in the form of:
http://<gateway>/foo/bar
http://<gateway>
Query arguments here are explicitly not allowed and trigger an intended
malformed url error.
There also was a crash when IPFS_PATH was set with a non trailing
forward slash. This has been fixed.
Lastly, a load of test cases have been added to verify the above.
Reported-by: Steven Allen
Fixes#12148Closes#12152
