BadSharedToken: make AEPST err msg optional

Add a configuration entry (aaf.av.alert_on_sharedtoken_errors - default
true) to tweak whether validation errors for sharedToken trigger the
BadSharedToken error page - obscuring the actual attribute list.
Merge code-develop into tuakiri-develop (BadSharedToken optional)
Messages: update messages-base from applicationbase
Messages: fix typos in error messages
Merge branch 'code-develop' into tuakiri-develop
Branding: Fit PDF on 1 page even with some err msg

Tweak the font sizes in _snapshot_pdf.gsp to fit the output on one PDF
A4 page even when some (one) error message is included.
Tests: SnapshotControllerSpec: turn BadSharedToken on

Adjust SnapshotControllerSpec to set
config.aaf.av.alert_on_sharedtoken_errors = true

to properly test SnapshotController even with changes introduced in
131c033f134670a3bcc6a9bf8a4f44a4863f3b4b
Config: switch off BadSharedToken view for Tuakiri

For tuakiri-deployments, set default config for
aaf.av.alert_on_sharedtoken_errors to false
Version: internal Tuakiri release 1.0-tuakiri1
Merge code-develop (1.0-tuakiri1) into tuakiri-develop