Introduce shallow and deep tags

[cliffano]

Other than health check type tags, we also need to introduce health check level tags.

• shallow will be executed very frequently (think an ELB doing a heartbeat), it should be minimum check that indicates that AEM is healthy, it shouldn't consume much resource on the server

• deep will be executed less frequent, it should give high level of confidence that AEM is healthy, it can consume some resource but obviously not to cause AEM itself to struggle

[lenuhc]

Closed with PR #12