Visualize an op

TLDR;

The opctl UI allows visualizing ops whether defined locally on the opctl host or remotely in a git repo.

If the op is defined remotely in a git repo and the git repo requires authentication, opctl will prompt for a username & password.

Local Op Example

1. Open a terminal and cd to any directory that contains ops somewhere in it's subtree.
2. Use the opctl ui subcommand to open the web UI to the current directory.

   opctl ui
3. Use the explorer panel to open and visualize an op.yml.
4. Try panning and zooming.

Remote Op Example

1. Open a terminal.
2. Use the opctl ui subcommand to open the web UI to the remote git tag github.com/opspec-pkgs/_.op.create#3.3.1.

   opctl ui github.com/opspec-pkgs/_.op.create#3.3.1
3. Use the explorer panel to open and visualize the op.yml.

   If any private remote refs are encountered and aren't cached, you'll be prompted for pullCreds.

4. Try panning and zooming.