Feature/#205 add mock data for starting a transaction

[loan21xw]

Describe your changes

• Respond with mock data on requests to POST /transactions, passing a specific transactionID (9999) every time, when a specific chargerID (100000) is used.

• Respond with mock data on requests to PUT /transactions/start/{transactionID} when the transactionID is a certain value (9999).

• Respond with mock data on requests to GET /transactions/{transactionID} when the transactionID is a certain value (9999).

• Respond with mock data on requests to PUT /transactions/stop/{transactionID} when the transactionID is a certain value (9999).

• Update API documentation in Swagger to accurately reflect the transaction part of the API

Issue ticket number and preferably a link

205

This change belongs to the following squad(s)

• Database
• [X] HTTP
• [X] OCPP

I have created unit tests for my code

• Yes
• [X] No
• No, I need help with this

Checklist before creating my pull request

• [X] My code is properly commented where needed
• [X] I have updated the documentation with my changes/additions
• [X] I have reviewed my code before creating this pull request
• [X] I have made sure that I am targeting the correct branch

[SweOlle]

Looks good. Nice implementation of the function to generate Mock-data.