Implement Admin Accounts API (Part 1/2)

[andregasser]

Mastodon's Admin Accounts API allows an admin to perform moderation action with accounts. The goal of this task is to implement the following endpoints of this API in BigBone:

• View accounts (v1)
• View accounts (v2)
• View a specific account
• Approve a pending account
• Reject a pending account

The Admin Accounts API as it is documented by Mastodon can be found here:
https://docs.joinmastodon.org/methods/admin/accounts/

Tip: A lot of other endpoints similar to this have already been implemented. In order to get an idea how to implement this, I suggest that you study the code upfront. Start with one of the *Methods.kt files.

Please consult the following documents to make sure your contribution meets our projects criteria:

• Code of Conduct
• Code Contribution Guidelines

[PattaFeuFeu]

It probably makes sense to wait for #333 to be reviewed and merged. I have made some decisions there that will likely influence the style of this issue here as well, such as:

• admin package