Display the harvest source identifier when listing harvest sources

[streino]

Neither the System (admin) UI nor the CLI display the harvest source identifier when listing sources.

CLI :

$ udata harvest sources
➢ Test harvest (dcat): 0 0 * * *
➢ ➢ Test harvest (dcat): 0 0 * * *

Admin :

The idendifier is needed for API or udata harvest commands, so it'd be nice to have it listed in those tools, instead of having to query the API to find it.

[maudetes]

Maybe not completely satisfying, but you can already see the id of the harvest source in the URL in the admin.