Add Abbreviation graphql layer

[aimee-mcneil-melville]

Fixes #6334

👩🏻‍💻 What does this PR do?

Adds graphQl layer for the abbreviations query + a service file

Can query by filter (optional)

This will allow the abbreviations to be used in the prescription directions

💌 Any notes for the reviewer?

🧪 Testing

• GraphQl endpoint testing - query abbreviations, you should have the option for expansion, id, and text
• Can query these fields to get all results
• Can query by the 'text' value of one abbreviation, and get the this abbreviation object

📃 Documentation

• Part of an epic: documentation will be completed for the feature as a whole
• No documentation required: no user facing changes or a bug fix which isn't a change in behaviour
• These areas should be updated or checked:
  1.
  2.