add interview logic and part of offer

[januschung]

For both interview and offer:

• add create table statements to schema.sql
• add mutation, type, query, input definition to schema.graphqls
• add model class definitions

More for interview:

• add controller, repository and service class
• add unit tests

Other change:

• refactor JobApplicationGraphQlTest to use mock instead of actual db (somehow it still rely on a in memory db which cause test data initialization and test data insertion problem. The fix is to generate a separate db per test script with random.uuid
• add more test to JobApplicationGGraphQlTest
• fix logging typo

[januschung]

@oseasmoran73 can you review when you have a chance?