Create column labels for tasks imported from Phabricator

Columns used on issue boards are available in the `maniphest.search like this:

        "columns": {
          "boards": {
            "PHID-PROJ-hihi": {
              "columns": [
                {
                  "id": 16,
                  "phid": "PHID-PCOL-haha",
                  "name": "Backlog"
                }
              ]
            }
          }

We'd need to add a label for each project phid we encounter in the boards key, and add a #{project_label}::#{column_label} label for each column we encounter nested in it.

We need to cache both the project-labels and column-labels in redis mapped to a GitLab label ID so we can reuse them for subsequent issues

/label ~"devops:manage"