Add api subcommand for arbitrary api calls not covered by existing subcommands (#879)

Reviewed-on: https://gitea.com/gitea/tea/pulls/879
Co-authored-by: techknowlogick <techknowlogick@gitea.com>
Co-committed-by: techknowlogick <techknowlogick@gitea.com>

cmd/cmd.go

@@ -59,6 +59,7 @@ func App() *cli.Command {
 
 			&CmdAdmin,
 
+			&CmdApi,
 			&CmdGenerateManPage,
 		},
 		EnableShellCompletion: true,