Add semantic validation of config files

[barnettwilliam]

To complement the structural validation the following additional validation should be carried out:

• [x] #115
• [ ] #116
• [ ] #117

[barnettwilliam]

Separated groups of validation checks into their own issues to be incrementally completed.

[szschaler]

We will put this on the back burner for now as a potential student project that would develop an actual configuration DSML using something like Langium, for example.