refactor: account related code

[lautarodragan]

This PR introduces several refactors and changes:

• enable typescript source maps
• refactor the old AccountController.create to remove business logic from router and avoid use of Mongoose's models
• installs mongodb
• introduce new architecture for GET /accounts/:issuer

New Architecture

New architecture drops use of Mongoose in favour of plain old MongoDB driver.

This allows us to avoid inheritance in our objects, have control of the interactions with the database without any behind-the-curtains magic, avoid global mutable objects and have models that are immutable objects of primitives with no functions in them.

It achieves this by introducing new files and keeping changes to old files to the bare minimum.

New controllers go in /controllers, new models in /models, new daos in /daos.

[poet-ci]

:tada: This PR is included in version 1.28.8 :tada:

The release is available on GitHub release

Your semantic-release bot :package::rocket: