Update adminguide's list of differences between client and embedded

The admin guide has a chapter that describes known differences between the client driver and the embedded driver: http://db.apache.org/derby/docs/10.10/adminguide/cadminapps.html

Most of this information was added for the original network client implementation in 10.1 (DERBY-371) and has not been updated since.

For example, http://db.apache.org/derby/docs/10.10/adminguide/cadminappsclientdiffs.html says SQLStates for exceptions on the client may be null. I believe this was fixed in 10.2 as part of DERBY-254.

It also says that SQLExceptions (and SQLWarnings) won't be chained, but that was fixed in 10.3 (DERBY-2692). That outdated information is also repeated here: http://db.apache.org/derby/docs/10.10/adminguide/radminapps811974.html