Implement createSettlement DB inserts

[ggrg]

Goal:

As a core OSS team member
I want to adapt existing codebase
so that createSettlement API handler successfully inserts all records to the DB

The story refers to OSS Settlement BRD, section 6.1.2.2 createSettlement

Tasks:

• Instantiate a settlement and settlement state [@ggrg]
• Change swagger definition to allow changed response [@ggrg]
• Generate and return response payload [@ggrg]
• Validate enhancement
• Fix existing unit tests
• Disable failing unit tests and add adjust todo note

Acceptance Criteria:

• A new settlement is successfully created
• Designs are up-to date
• Unit Tests pass
• Integration Tests pass
• Code Style meets standards
• Coverage meets standards

Pull Requests:

• feature/1097 Create Settlement Changes #2 central-settlement#225

Follow-up:

• Implement Update the progress of a settlement #1099

Dependencies:

• Change createSettlement API definition and validations #1096

Accountability:

• Owner: TBC
• QA/Review: TBC