Add app delegate command

[bgins]

Summary

Problem

There is currently no way within the rust code to way to give permission for other DID keys to make changes to a site created with this CLI.

Impact

Without this ability users won't be edit their site from another computer and wont be able to edit it all if something were to happen to the DID.

Solution

Create a new command that allows the user to give permissions to other DIDs to edit the site.

Details

Currently the code for running the command fission app delegate is written in Haskell. See more about this problem here.