Define v2 api endpoint

[jeremy-babylonlabs]

due to the updated folder structure, there are alot of files changes. but the main difference would be grouping the shared api, queue and db functions in shared directory, while version specific files and functions are placed in v1 and v2 dir.

the latest v2 api endpoints and mock response can be found in internal/v2/api and shared/api dir.

closes #67

[jrwbabylonlab]

@jeremy-babylonlabs the issue with the swagger failure is due to types are moved to other places.
So for example, the PublicResponse was under the same package before, but now moved to other places, hence you need to make sure the path is correct in swagger definition.

[gusin13]

overall lgtm, great work.

few notes/q's

1. i am assuming the local setup is running ok after this v1/v2 regrouping?
2. some ci jobs are failing

[jeremy-babylonlabs]

#86

merging, will improve the handlers on another PR