Update to trixie base, and a few other updates

[realtyem]

The docker image was based on debian-bookworm. Well that is starting to lose support, and the base Synapse image has already been moved to trixie. There will have to be a few other changes to support this migration:

• redis/keydb -> valkey
• nginx 1.24 -> nginx 1.29
• synapse-tools -> bookworm:trixie, golang1.22:golang1.25

Went ahead and brought Complement testing up to current. This probably isn't needed, as comprehensive endpoint testing isn't something I'm concerned about. Only that nothing got broken

Fixes:

• Docker build fails due to libhiredis0.14 #22

[realtyem]

The testing suite got a merge that is not included in the last release of Synapse's docker image, so the testing will fail until that actual fix comes around. Merging anyway, it's unlikely there is an actual problem

[realtyem]

The valkey update did not go smoothly. My attempts to use just the built application from the bitnami docker image, and then the actual valkey/valkey image failed. I suspect a dependency was missing that it did not complain about properly, but other than an annoying huge stack trace with a bunch of things that were not helpful to telling my why, I had nothing. Installing valkey from the package manager instead. It won't be the latest and greatest, but at least it works again while I can now take some time to investigate

Everything else seems to be working well