Create a good EntityValueProvider for Spring fuzzing

[EgorkaKulikov]

Description

Entities in Spring projects sometimes have many specific annotations to validate field values.
See, for example, https://github.com/spring-projects/spring-petclinic/blob/main/src/main/java/org/springframework/samples/petclinic/owner/Owner.java

Fuzzing this issue, we firstly construct some bad objects and improve it to good state with mutations (this process is not guarantied to be successful).

It will be better to create an object satisfying all requirements on the construction phase.