fix(ci): move Eclair docker files to tests/docker/

The workflow references tests/docker/ paths after the upgrade-test-deps rebase,
but the Eclair compose and Dockerfile were still at the repo root.
Also aligns bitcoind image version to 29.1 for consistency.

Author: febyeji

Dockerfile.eclair tests/docker/Dockerfile.eclairDockerfile.eclair renamed to tests/docker/Dockerfile.eclair

@@ -5,7 +5,7 @@ services:
   # causing Eclair to fall behind the chain tip. Host networking avoids
   # this by keeping all inter-process communication on localhost.
   bitcoin:
-    image: blockstream/bitcoind:30.2
+    image: blockstream/bitcoind:29.1
     platform: linux/amd64
     network_mode: host
     command: