Config file samples update problem

[artur-intech]

Currently, if something in sample config files is changed (say in application-example.yml), it is quite easy to miss this fact, and forget to make corresponding changes in application.yml.

Same problem applies to other projects as well, whereas being most important (IMHO) in registry given its size.

@maciej-szlosarczyk Had some ideas, such as employing Ansible to fix this problem.

[artur-intech]

One option is just to implement some build script, which would compare keys from application.yml with the ones from application-example.yml.

[teadur]

will be solved together with #690