webdav: Drop plain https connector

Drops the Java https connector and renames https-jglobus to
https.

In the past, the main benefit of having a non-JGlobus connector was that it
didn't use the old PureTLS implementation, and optionally supported
asynchronous I/O. With the rewritten support for JGlobus, the two connectors
were much more similar than in the past, sharing both the I/O path and the TLS
implementation. The only difference between them in dCache 2.11 is how they
deal with certificates, and the JGlobus based one is more powerful in that
respect.

The webdav.authn.protocol=https-jglobus value is now just an alias for https.
webdav.authn.keystore, webdav.authn.keystore.password, webdav.authn.truststore,
and webdav.authn.truststore.password are now forbidden properties.

Target: trunk
Require-notes: yes
Require-book: yes
Acked-by: Paul Millar <paul.millar@desy.de>
Patch: https://rb.dcache.org/r/7420/