Add support for Import Specification

[tkilias]

Background:

• Currently, the mock doesn't support import specification

Acceptance criteria

• User needs to be able to specify that he wants to run the import specification
• User needs to be able to validate the output of the import specification regarding its test criteria
• User needs to be able to provide parameters to the import specification
• the mock should validate the input and output to the import specification regarding it is valid for the UDF protocol