DNN-4755, Allow for more tokens in CoreMessaging E-Mails

As described in the ticket; this will allow for more tokens and therefor
greater flexibility in the core messagin template. It's just adding a
few more tokens with no impact on anything else.
Improved Tokenreplce
DNN-5601 Allow specifying null type to GetValue and GetValueOrDefault
Build localization into list entries so they can be localized by dropping a resource file into the App_GlobalResources folder. This would take care of DNN-5568.
Fix DNN-5629: RoleController.DeleteRole() now removes UserInfo objects from data cache as they have been modified
DNN-5361 Config manager upload button always active
Add code documentation in AJAX.cs
CONTENT-2699 - Updated version to 7.3.3
DNN-5648 / SOCIAL-3344 Upgrade fails
Content-2671: exclude modules in admin category.
DNN-5687 User account settings are not applied at host user accounts
DNN-5671 Message on Languages module reads "DotNetNuke"
Content-2671: include module actions js in script block control.
Revert "Content-2671: include module actions js in script block control."

This reverts commit 603be6a0605647ee0591ae441efdaa3c5ccdbc62.
correct message
Fix type

fix a misleading typo (twice)
When only [Cacheable] is used without any addtional attributes, the system defaults to a timeout and priority of zero, which doesn't work all that great.
reduce calls to sql for non-existent users
CONTENT-2554 - FileCrawler: ModifiedTimeUTC invalid error when overwrite a file with workflow enabled.
Fixed DNN-5692: Handle invalid paths in DotNetNuke.Modules.Admin.Extensions.AvailableExtensions.IconExists()