Add a health check endpoint

[DavisRayM]

Suggested Feature / Enhancement

Currently the application provides no way of knowing whether all the core parts(Database connection, Cache connection, e.t.c) are working as expected. It would help quite a lot if an endpoint was added that provided such information rather than requiring a user to hit a data endpoint or something of the sort

Benefits of implementing the feature/enhancement

• Easier to retrieve application status

Suggested implementation plan(Steps to be taken to implement feature)

• N/A

[DavisRayM]

Some statuses that would be nice to have on the endpoint (This is not a definitive list):

• Postgres / Database status
• Cache status
• Messaging app status ? Whether MQTT requests are successful e.t.c ?