* introduce a fallback handler that checks that role is Viewer.
* update UI nav links to allow alerting tabs for anonymous user
* update rule api to check for Viewer role instead of SignedIn when RBAC is disabled
* add check for access to rule's data source in GET APIs
* use more general method GetAlertRules instead of GetNamespaceAlertRules.
* remove unused GetNamespaceAlertRules.
Tests:
* create a method to generate permissions for rules
* extract method to create RuleSrv
* add tests for RouteGetNamespaceRulesConfig
* move validation at the beginning of method
* remove usage of GetOrgRuleGroups because it is not necessary. All information is already available in memory.
* remove unused method
* Alerting: Accurately set value for prom-compatible APIs
Sets the value fields for the prometheus compatible API based on a combination of condition `refID` and the values extracted from the different frames.
* Fix an extra test
* Ensure a consitent ordering
* Address review comments
* address review comments
* Alerting: Remove internal labels from prometheus compatible API responses
* Appease the linter
* Fix integration tests
* Fix API documentation & linter
* move removal of internal labels to the models
