Add app delegate command (#606)

* Add app delegate command stub

* Add app registration check

* Add lifetime in seconds option

* Read key and UCAN from environment

* Add DID ParseError

* Add UCAN ParseError

* Add proof token check

* Add an error when delegating without UCAN env var

* Add an error when delegating without machine key

Both machine key and UCAN must be set to delegate using
environment variables.

* Print delegated UCAN on success

* Separate user config and env var proof checks

The check from user config might be a root credential, but the
environment variable will not. The user config check may get an index of
apps from the server.

* Check user config UCAN for capability

* Add check for remote option

Check for the remote to support staging, localhost, and other
remotes.

* Add quiet flag

Command only outputs the UCAN with this flag. Quiet mode makes it easier
to use UCANs in a non-interactive use cases.

* Add potency option

Potency can be AppendOnly, Destroy, or Super_User. Defaults to
AppendOnly.

* Change AppendOnly to Append in help and errors

fission-cli/library/Fission/CLI/App.hs

@@ -20,6 +20,7 @@ import qualified Fission.CLI.Handler                     as Handler
 import           Fission.CLI.Handler.Error.Types         (Errs)
 
 import           Fission.CLI.Parser.Command.App          as App
+import qualified Fission.CLI.Parser.Command.App.Delegate as App.Delegate
 import qualified Fission.CLI.Parser.Command.App.Info     as App.Info
 import           Fission.CLI.Parser.Command.App.Init     as App.Init
 import           Fission.CLI.Parser.Command.App.Up.Types as App.Up
@@ -38,6 +39,9 @@ interpret baseCfg cmd = do
   logDebug @Text "App interpreter"
 
   case cmd of
+    Delegate App.Delegate.Options {appName, potency, audienceDid, lifetimeInSeconds, quiet} ->
+      Handler.delegate appName potency audienceDid lifetimeInSeconds quiet
+
     Info App.Info.CommandOnly ->
       Handler.appInfo
 

fission-cli/library/Fission/CLI/Handler.hs

@@ -1,5 +1,6 @@
 module Fission.CLI.Handler
-  ( module Fission.CLI.Handler.App.Info
+  ( module Fission.CLI.Handler.App.Delegate
+  , module Fission.CLI.Handler.App.Info
   , module Fission.CLI.Handler.App.Init
   , module Fission.CLI.Handler.App.Publish
   --
@@ -10,6 +11,8 @@ module Fission.CLI.Handler
   , module Fission.CLI.Handler.User.Whoami
   ) where
 
+import           Fission.CLI.Handler.App.Delegate
+
 import           Fission.CLI.Handler.App.Info
 import           Fission.CLI.Handler.App.Init
 import           Fission.CLI.Handler.App.Publish