Migrate to Github Actions

Now Travis has stopped providing a free tier migrate initial
tests over to use Github Actions.

tests/ci/idle_agenda.yaml

@@ -0,0 +1,23 @@
+config:
+    iterations: 1
+    augmentations:
+        - ~~
+        - status
+    device: generic_local
+    device_config:
+        big_core: null
+        core_clusters: null
+        core_names: null
+        executables_directory: null
+        keep_password: true
+        load_default_modules: false
+        model: null
+        modules: null
+        password: null
+        shell_prompt: !<tag:wa:regex> '40:^.*(shell|root|juno)@?.*:[/~]\S* *[#$] '
+        unrooted: True
+        working_directory: null
+workloads:
+-   name: idle
+    params:
+        duration: 1