Add a unified/canonical URI scheme for cluster connections

[nevali]

e.g.:

static:///?key=clusterkey&env=live&instid=uuid&partition=gold`
pgsql://user:pass@host/db_name/?key=clusterkey&env=live&instid=uuid&partition=gold`

Tracked as RESDATA-1272

[nevali]

Depends upon bbcarchdev/liburi#5