Move ethereum-serai under the processor

It isn't generally usable and should be directly integrated at this point.

.github/workflows/tests.yml

@@ -52,6 +52,7 @@ jobs:
             -p serai-processor-signers \
             -p serai-processor-bin \
             -p serai-bitcoin-processor \
+            -p ethereum-serai \
             -p serai-ethereum-processor \
             -p serai-monero-processor \
             -p tendermint-machine \