Move plugins to manifest, pin Docker version, add Makefile

- Add plugins.txt listing all plugins for reproducible installs
- Add Makefile with setup/start/stop/install-plugins targets
- Remove user/plugins/ from git tracking
- Pin Docker image to 1.7.49.5-ls244

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

plugins/email/vendor/symfony/redis-messenger/CHANGELOG.md

@@ -1,34 +0,0 @@
-CHANGELOG
-=========
-
-5.4
----
-
- * Deprecate not setting the `delete_after_ack` config option (or DSN parameter),
-   its default value will change to `true` in 6.0
-
-5.3
----
-
- * Add `rediss://` DSN scheme support for TLS protocol
- * Deprecate TLS option, use `rediss://127.0.0.1` instead of `redis://127.0.0.1?tls=1`
- * Add support for `\RedisCluster` instance in `Connection` constructor
- * Add support for Redis Cluster in DSN
-
-5.2.0
------
-
- * Added a `delete_after_reject` option to the DSN to allow control over message
-   deletion, similar to `delete_after_ack`.
- * Added option `lazy` to delay connecting to Redis server until we first use it.
-
-5.1.0
------
-
- * Introduced the Redis bridge.
- * Added TLS option in the DSN. Example: `redis://127.0.0.1?tls=1`
- * Deprecated use of invalid options
- * Added ability to receive of old pending messages with new `redeliver_timeout`
-   and `claim_interval` options.
- * Added a `delete_after_ack` option to the DSN as an alternative to
-   `stream_max_entries` to avoid leaking memory.