Add support for proxy networks & cleanup playbook vars

playbooks/vars/environment.yaml

@@ -0,0 +1,15 @@
+---
+# GitHub may rate limit unauthenticated API requests, this is more likely when
+# behind a network proxy. Set the GITHUB_TOKEN environment variable to
+# authenticate any GitHub API requests executed while playing roles.
+github_auth_headers: >-
+  {{ { 'Authorization': 'Bearer ' + lookup('env', 'GITHUB_TOKEN') }
+      if lookup('env', 'GITHUB_TOKEN') else {} }}
+
+# When working behind a network proxy, set the http_proxy and https_proxy
+# environment variables. These will be passed through to uses of the `get_url`
+# module when playing roles.
+proxy_environment: >-
+  {{ { 'http_proxy': lookup('env', 'http_proxy'),
+       'https_proxy': lookup('env', 'https_proxy') }
+      if lookup('env', 'http_proxy') and lookup('env', 'https_proxy') else {} }}