Enable MetaCentrum OpenStack

Gotchas:
- LSAN_OPTIONS suppression= require debug symbols and llvm-symbolizer
(and therefore the llvm package). Without this, ASAN builds fail.

- image building requires HW virtualization, MetaCentrum OpenStack
doesn't support that in those nodes/flavors where I have access

- I'm not using OpenStack's disk-image-builder (DIB) because it needs
root, and I'm not used to disk image building needing root, sorry

...which means that image upload is a manual op, unfortunately.

Change-Id: I76e2f760f7b6dba8587c635c0532837915a06aec
diff --git a/files/nodepool/nodepool.yaml b/files/nodepool/nodepool.yaml
index 32c740e..2b6f76b 100644
--- a/files/nodepool/nodepool.yaml
+++ b/files/nodepool/nodepool.yaml
@@ -15,9 +15,41 @@
     min-ready: 4
     max-ready: 4
 
+  - name: f31
+
+  - name: f31-small
+
   - name: webgen-f29
 
 providers:
+  - name: metacentrum
+    driver: openstack
+    cloud: metacentrum
+    region-name: 'brno1'
+    launch-timeout: 300
+    cloud-images:
+      - name: f31
+        image-name: ci-zuul-f31--2020-04-20--1
+        username: ci
+    pools:
+      - name: main
+        networks:
+          - net1
+        security-groups:
+          - default
+        max-servers: 2
+        max-cores: 40
+        max-ram: 131072
+        labels:
+          - name: f31
+            cloud-image: f31
+            flavor-name: standard.one-to-many
+            key-name: zuul
+          - name: f31-small
+            cloud-image: f31
+            flavor-name: standard.small
+            key-name: zuul
+
   - name: potemkin-runc
     driver: runc
     pools: