[Feature] Custom choices

[hjoaquim]

1. Why?:

   • Platform clients need more info on the available choices for certain parameters, which can't use Literal directly.

2. What?:

   • Adds a way of custom adding choices to the arguments so that Platform clients can leverage this info.
     1. Adds OpenBBCustomChoices which is then used on the statics assets to store the choice information.
     2. By leveraging json_schema_extra this info automatically is set up on the openapi.json.

3. Impact (1-2 sentences or a bullet point list):

   • Minor change in the UX, only perceivable when navigating to the command implementation (python) or the openapi.json.
   • Also might introduce some maintenance impact as adds a "new" way of adding choices.
   • Impact score: 5

User Experience (UX) Impact: 1 Performance Impact: 0 Compatibility Impact: 1 Security Impact: 0 Scalability Impact: 1 Maintenance Impact: 2 Compliance Impact: 0 Dependency Impact: 0

4. Testing Done:

   • Running the PackageBuilder
   • Running the Rest API and navigating to /openapi.json