STORE-122 and 184

The fixes involve a validation to check if fields marked as required have values.
The test for a value is performed after removing white spaces and the undefined keyword which sometimes appears when converting data from the post request to a model. (Note: This undefined value most likely originates from the client script used to craft the request).

Changes:
- Added a validate method to the model class which runs all validations defined in the validations folder config/ext/validations 
- The model is validated before creating a new asset
- The model is validated before performing any updates
-If a validation fails an error report object is generated containing the violations on a per field by field basis
-Changed the client side scripts to display the error report