Improving ValidationUtils

[staudtMarius]

There are two main points in class ValidationUtils :

• non critical validations (e.g. geometry) should no longer throw exceptions instead their validation results should be logged.
• all thrown exceptions should be collected and thrown at the end of the validation process using the Try class introduced in Refactor data source to throw exception instead of returning optionals #712

TO

• Check uniqueness of identifiers
• Implement a connectivity check, as done in SIMONA in GridModel.validateConnectivity as part of the container validation utils

[t-ober]

I added another item:

Currently we do not check whether ids of all the elements of a type (e.g. PvInputs) are unique. This is something we require in Simona simulations, so it makes sense to check that and at least issue a warning, maybe even throw an exception.