refactor: copy in central-settlement codebase

[lewisdaly]

Copies across central-settlement into the central-ledger codebase. This is necessary step for the TigerBeetle Integration.

The settlement api is now available under /v2/:

$ npm run start

> @mojaloop/central-ledger@19.14.0 start
> npm run start:api


> @mojaloop/central-ledger@19.14.0 start:api
> node src/api/index.js
...

method  path                                                       description
------  ---------------------------------------------------------  ----------------------------------------------------------------------
// Existing routes:
GET     /documentation
GET     /enums
GET     /health
GET     /ledgerAccountTypes                                        Get all ledger Account types
POST    /ledgerAccountTypes                                        Create a new ledger account type
GET     /metrics                                                   Prometheus metrics endpoint
GET     /participants
POST    /participants
...

// New routes added from central-settlement:
GET     /v2/api-docs                                               The OpenAPI document.
GET     /v2/health                                                 Gets the health of the service and sub-services (i.e. database).
GET     /v2/settlements                                            Returns Settlements as per parameter(s).
POST    /v2/settlements                                            Triggers settlement creation. Returns settlement report.
GET     /v2/settlements/{id}                                       Returns Settlement(s) as per parameters/filter criteria.
PUT     /v2/settlements/{id}                                       Acknowledgement of settlement by updating with Settlement Id.
GET     /v2/settlements/{sid}/participants/{pid}                   Returns Settlement(s) as per filter criteria.
PUT     /v2/settlements/{sid}/participants/{pid}                   Acknowledgement of settlement by updating the reason and state by SP.
GET     /v2/settlements/{sid}/participants/{pid}/accounts/{aid}    Returns Settlement(s) as per filter criteria.
PUT     /v2/settlements/{sid}/participants/{pid}/accounts/{aid}    Acknowledgement of settlement by updating the reason and state by SPA.
GET     /v2/settlementWindows                                      Returns Settlement Windows as per parameter(s).
GET     /v2/settlementWindows/{id}                                 Returns a Settlement Window by id.
POST    /v2/settlementWindows/{id}                                 Closes requested window and opens a new one.

Additionally, this architecture change will make the total codebase much simpler by:

1. Reducing the number of repositories.
2. central-ledger will no longer need to publish a @mojaloop/central-ledger package for consumption by central-settlement.
3. Reducing the total number of docker images in a deployment.

So we go from this dependency tree:

To this dependency tree:

I chose to keep the settlement code under src/settlement for now to simplify the review process, and make it easier in the short term to keep the two repositories in sync with one another.

For deployments, we have 2 options (we may want to choose either depending on the scenario):

1. Run the central-ledger container in the place of the settlement container, essentially running central-ledger as settlement.
2. We remove the central-settlement container altogether, and update routes accordingly.

Recommended Followup Processes:

1. Merge this PR.
2. Release a preview central-ledger and test.
3. Mark the central-settlement repository as archive only.
4. Come back and refactor the settlement code in this repository:
   1. Distribute the code under src/settlement into the appropriate places in src/.
   2. Likewise with the code in test/settlement.

[sonarqubecloud]

Quality Gate failed

Failed conditions
4 Security Hotspots
21.8% Duplication on New Code (required ≤ 3%)
D Reliability Rating on New Code (required ≥ A)

See analysis details on SonarQube Cloud

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