Add health checks

[alexbohomol]

• Implement database checks
• Setup UI for checks and history storage
• Cover with system/UI testing

References:

• https://blog.devart.com/how-to-implement-health-checks-in-asp-net-6.html - tried to employ UI for health checks, but final result does not look as mature
• Extend httpResponseMessage.Should().HaveStatusCode() to dump request body on failure fluentassertions/fluentassertions#1811
• https://www.continuousimprover.com/2016/05/the-definitive-guide-to-extending.html
• https://www.continuousimprover.com/tags/#fluent-assertions
• https://github.com/balanikas/FluentAssertions.Http
• https://github.com/adrianiftode/FluentAssertions.Web
• https://dev.to/fabriziobagala/fluent-assertions-fluently-assert-the-result-of-net-tests-2nie