Unify streams URI

Unify streams URI

We have a tad inconsistent delivery of events:
- SSE binds to /rests/notif
- WS binds to /xyz (with special prefixes)

Unify handling so that we bind to /rests/events irrespective of the
protocol we use. This eliminates the need for WS to know the exact
naming of streams (to intercept them).

Also update WS to:
- use URI.getPath(), as we want the decoded stream name
- perform path stripping without createStreamNameFromUri(), as that
  method is just confusing and unnecessary

JIRA: NETCONF-1102
Change-Id: I4c67b443d9cbe6feb9d5e5225115d37ba609a86a
Signed-off-by: Robert Varga <robert.varga@pantheon.tech>