[NX-506] Properly calculate error key out of violation property path

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
Remove obsolete @NotNull validation in case @NotEmpty is present

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
Replace @NotNull with @NotEmpty where appropriate

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
Merge pull request #588 from sonatype/fix-notempty-validation

REVIEW: @NotEmpty related fixes
Kill Nexus421PlainNotificationIT
Remove more check_smtp_settings leftovers in ui and testsuite
Set 'short' as default date column format

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
nukeProxyCaches coupled with new expireCaches behaviour was throwing off the request count, so move this call to before the count is reset
Fix validation of logger level (@NotEmpty doesn't make sense for enumeration)
Merge remote-tracking branch 'origin/master' into NEXUS-6591-open-up-ldap