Merge pull request #388 from shackbarth/20254-globalfold

issue #20254: added usrext table
change your own password
admin change user password: client-side
Issue #20254 consolidate assets into sessionless static file location.
Issue #20254 namespace client URLs to example.com/database-name/app
Issue #20254 send database name in XT.dataSource.request's options.
Issue #20254 namespace SessionStore and access through the right database.
Issue #20254 namespace cookies, make login and assets sessionless, namspace client paths.
Issue #20254 namespace file path.
overriding backbone save for user_account
Merge remote-tracking branch 'XTUPLE/20254-global' into 20254-globalfold
merge with ben