Record where templates were installed from

[itowlson]

This adds a spin templates list --verbose flag which adds an "installed from" column to the table:

+-----------------------------------------------------------------------------------------------------------------+
| Name                Description                                          Installed from                         |
+=================================================================================================================+
| http-grain          HTTP request handler using Grain                     /home/ivan/github/spin                 |
| http-js             HTTP request handler using Javascript                https://github.com/fermyon/spin-js-sdk |
| http-php            HTTP request handler using PHP                       /home/ivan/github/spin                 |

If there is no record (as there won't be for templates installed before this patch) then the column is blank; it will get populated on next update.

This will also provide a foundation for a simpler update/sync experience in a future thrilling episode.

Signed-off-by: itowlson ivan.towlson@fermyon.com