* Make identity.Requester available at Context
* Clean pkg/services/guardian/guardian.go
* Clean guardian provider and guardian AC
* Clean pkg/api/team.go
* Clean ctxhandler, datasources, plugin and live
* Question: what to do with the UserDisplayDTO?
* Clean dashboards and guardian
* Remove identity.Requester from ReqContext
* Implement NewUserDisplayDTOFromRequester
* Fix tests
* Change status code numbers for http constants
* Upgrade signature of ngalert services
* log parsing errors instead of throwing error
* Fix tests and add logs
* linting
