This is a prerequisite to writing a validator-validator.

Also add a couple of extra standard rules (enum constants).

This allows a validator builder to import rules
for validating its base type.  Also fix issue with manifest.

This is just the first test, to prove that in a "happy path"
scenario, the validator-validator can validate itself.

Note that Validation has its own Parallelizable attribute,
easy to mudle them up!

This removes all of the class inheritance from the Validation
Manifest object model (I will do the Manifest Model later).
This is done to make it easier to deal with recursive manifest
items.  It will now be easier to create:

* Recursive collection items
* Recursive polymorphic types

This moves the assembling of manifest items into
a context class, rather than trying to do it inside the builders.

The validation-manifest validator needs review, because the
object model has changed somewhat since it was first designed.
Also, I am unaware of my current test coverage %.

This commit should successfully build though.

This marks up some non-implemented functions, so
SonarCloud reminds me about them, as well as fixing
a minor tech issue.

#33 validator validation

This removes some of the class hierarchy related to
the manifest model, and replaces it with something simpler.

This is a result of publishing the docs site manually.
Bizzarely it stopped working somewhere between:

  6f89da3
and
  d81bcce

...whilst I was working on #33.

I've removed the build step to auto-publish them and
I'm going to have to create an issue to investigate what's
happened there.