feat(valkey): add ansible role

roles/valkey/README.md

@@ -0,0 +1,13 @@
+# `finallycoffee.databases.valkey` ansible role
+
+Valkey is an open source (BSD 3 licensed), high-performance in-memory key/value
+data store, ideal for workloads like caching or message queues. It has been
+forked from redis 7.2.4 before redis license was changed to SSPL.
+
+Valkey offers compatibility to redis and can be used as a drop-in replacement
+for redis.
+
+## Configuration
+
+For the configuration, see the [`redis` role configuration](../redis/README.md#configuration),
+and swap the `redis_` prefix of all variables for the `valkey_` prefix.