tools(ci): add script to build all examples

Using new cmake project declare.

tools/ci/envsubst.py

@@ -0,0 +1,27 @@
+#!/usr/bin/env python
+#
+# A script similar to GNU envsubst, but filters out
+# some CI related variables.
+
+import os
+import sys
+
+
+def main():
+    # Sanitize environment variables
+    vars_to_remove = []
+    for var_name in os.environ.keys():
+        if var_name.startswith('CI_'):
+            vars_to_remove.append(var_name)
+    for var_name in vars_to_remove:
+        del os.environ[var_name]
+
+    for line in sys.stdin:
+        if not line:
+            break
+        sys.stdout.write(os.path.expandvars(line))
+    sys.stdout.flush()
+
+
+if __name__ == '__main__':
+    main()