Remove joinsession

[dominikl]

Following discussion https://github.com/ome/openmicroscopy/pull/6319 . Removes the calls to client.joinSession, only client.createSession is used. The check for session id login is kept, because the gateway uses it to decide if the session can be closed on disconnect.

The implications for clients are:

• Gateway.joinSession method doesn't exist any longer
• For session ID login the ID has to be passed as username and password. Before username was enough.

(replaces https://github.com/ome/omero-gateway-java/pull/62 )

[jburel]

For session ID login the ID has to be passed as username and password. Before username was enough. Insight has not been modified to match that statement.

[dominikl]

Not quite sure what you mean. Insight will be the same, you have to use the id as username and password. I just still had to update the tooltip, which said use it only for the username (https://github.com/ome/omero-insight/pull/296 )

[jburel]

in insight you only need to put the sessionID as username I think. I need to double-check

[dominikl]

Not with this PR. The check if a username is a session id was dealt with in the gateway.

[jburel]

the joinSession method has been deprecated for a while. The change makes sense.