New functionality for enabling/disabling and inspecting runners

This MR introduces the following features:

1. Consolidate all gitlab-related commands under the command "gitlab"
2. Add a new command "gitlab runners" to manage runners in projects (enable/disable)
3. Add a new command "gitlab jobs" to list jobs in shared runners

bob/devtools/scripts/jobs.py

+#!/usr/bin/env python
+
+import os
+
+import click
+
+from . import bdt
+from ..release import get_gitlab_instance
+
+from ..log import verbosity_option, get_logger, echo_normal
+logger = get_logger(__name__)
+
+
+@click.command(epilog='''
+Examples:
+
+  1. List running jobs on a runner defined by its description (macmini):
+
+     $ bdt gitlab jobs -vv macmini
+
+''')
+@click.argument('name')
+@click.option('-s', '--status', type=click.Choice(['running', 'success',
+  'failed', 'canceled']),
+    default='running', show_default=True,
+    help='The status of jobs we are searching for - one of "running", ' \
+        '"success", "failed" or "canceled"')
+@verbosity_option()
+@bdt.raise_on_error
+def jobs(name, status):
+    """Lists jobs on a given runner
+    """
+
+    gl = get_gitlab_instance()
+    gl.auth()
+    user_id = gl.user.attributes['id']
+
+    # search for the runner to affect
+    the_runner = [k for k in gl.runners.list(all=True) if \
+        k.attributes['description'] == name]
+    if not the_runner:
+      raise RuntimeError('Cannot find runner with description = %s', name)
+    the_runner = the_runner[0]
+    logger.info('Found runner %s (id=%d)',
+        the_runner.attributes['description'], the_runner.attributes['id'])
+
+    jobs = the_runner.jobs.list(all=True, status=status)
+    logger.info('There are %d jobs running on %s', len(jobs), name)
+    for k in jobs:
+      echo_normal('** job %d: %s (%s), since %s, by %s [%s]' % \
+          (k.id, k.attributes['project']['path_with_namespace'],
+        k.attributes['name'], k.attributes['started_at'],
+        k.attributes['user']['username'], k.attributes['web_url']))