fix #5005 - adds versioning (ie. fingerprinting) for static assets - core, modules, and themes.

[sbwalker]

As part of implementing fingerprinting, the following enhancements were introduced:

• Version field added to Theme table and updated each time version changes (which also updates the ModifiedOn field)
• update the ModifiedOn field in the ModuleDefinition table when the version changes
• new InstallationVersion and InstallationDate properties included in appsettings.json which are updated whenever the core framework version changes
• GenerateSimpleHash method introduced in Utilities
• Version property introduced in Resource class which adds fingerprinting to Urls