[NEXUS-5900] Drop security on/off checkbox from server settings UI

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
[NEXUS-5902] Make anonymous an administrator when security is disabled

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
[NEXUS-5903] Remove rest API for settings security enabled/disabled

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
Merge remote-tracking branch 'origin/master' into NEXUS-5899-disable-security
[NEXUS-5901] Warn user about the fact that security has been enabled on upgrade

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
[NEXUS-5903] Remove config/api for disabling security

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
[NEXUS-5902] Use a shire thread bounded all rights subject in case that tests should run with security disabled

+ remove direct calls to security system/config to disable security

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
[NEXUS-5899] Do not store the upgraded file to ${plexus-home}/conf as that may interfere with other tests depending on test ordering

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
[NEXUS-5902] Make Nexus421PlainNotificationIT a secure test to avoid emails being sent also to anonymous user

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
[NEXUS-5899] Upgrade default test security-configuration.xml to 2.0.7

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
[NEXUS-5902] Do not update user roles if not necessary

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
[NEXUS-5899] Drop useless memory realms & UTs / ITs related to it

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
Merge remote-tracking branch 'origin/master' into NEXUS-5899-disable-security
Merge pull request #162 from sonatype/NEXUS-5899-disable-security

REVIEW: [NEXUS-5899] Remove ability to disable security