Update README.md and container-images.md: replace links to the original synapse-admin with ones to its fork

The original synapse-admin (Awesome-Technologies/synapse-admin) was replaced with etke.cc/synapse-admin with 73d338d9d1 on Sep 12, 2024.

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

docs/container-images.md

@@ -110,7 +110,7 @@ These services are not part of our default installation, but can be enabled by [
 
 - [gnuxie/draupnir](https://hub.docker.com/r/gnuxie/draupnir) - the [Draupnir](https://github.com/the-draupnir-project/Draupnir/) moderation bot (optional)
 
-- [awesometechnologies/synapse-admin](https://hub.docker.com/r/awesometechnologies/synapse-admin) - the [synapse-admin](https://github.com/Awesome-Technologies/synapse-admin) web UI tool for administrating users and rooms on your Matrix server (optional)
+- [etke.cc/synapse-admin](https://ghcr.io/etkecc/synapse-admin) - the [etkecc/synapse-admin](https://github.com/etkecc/synapse-admin) (a [feature-rich](https://github.com/etkecc/synapse-admin#fork-differences) fork of [Awesome-Technologies/synapse-admin](https://github.com/Awesome-Technologies/synapse-admin) web UI tool for administrating users and rooms on your Matrix server (optional)
 
 - [prom/prometheus](https://hub.docker.com/r/prom/prometheus/) - [Prometheus](https://github.com/prometheus/prometheus/) is a systems and service monitoring system