utils: Handle datetime objects in shorttime/shortdate (bnc#874162)
report: Resolve datetime/timestamp mixup (bnc#874162)

Amends commits 354228 and 333020
clidisplay: Remove singleton for CliDisplay
term: Turn TerminalController into a module
cache: Turn WCache singleton into module
idmgmt: Turn IdMgmt singleton into module
schema: Convert schema singleton to module
msg: ErrorBuffer doesn't need to be a singleton
report: Report doesn't need to be a singleton
cibconfig: CibFactory doesn't need to be a singleton
cibstatus: Remove usage of Singleton
singletonmixin: Remove the singleton mixin as it's no longer used
dev: Remove reference to singletonmixin
cibconfig: Eliminate external use of is_cib_sane()