cloud: add image build for GCP

Depends on the kickstart for GCP getting merged:
https://pagure.io/fedora-kickstarts/pull-request/690#

Signed-off-by: Dusty Mabe <dusty@dustymabe.com>
(cherry picked from commit 783f489ad7188374843ce122ffd28eab236bd2c0)

fedora.conf

@@ -354,6 +354,25 @@ image_build = {
                     'failable': ['ppc64le', 's390x'],
                      }
         },
+        {
+            'image-build': {
+                    'format': [('gce', 'tar.gz')],
+                    'name': 'Fedora-Cloud-Base-GCP',
+                    'kickstart': 'fedora-cloud-base-gcp.ks',
+                    # Use `Fedora-30` profile here because we need it
+                    # to be a UEFI image and currently OZ does that if
+                    # we use the `Fedora-30` profile.
+                    'distro': 'Fedora-30',
+                    # GCP engineers have told me the disk images have bad
+                    # performance if they are anything less than 10G
+                    'disk_size': 10,
+                    'arches': ['x86_64'],
+                    'repo': 'Everything',
+                    'install_tree_from': 'Everything',
+                    'subvariant': 'Cloud_Base',
+                    'failable': ['x86_64'],
+                     }
+        },
         {
             'image-build': {
                     'format': [('vagrant-libvirt','vagrant-libvirt.box'), ('vagrant-virtualbox','vagrant-virtualbox.box')],