[chronik] Reduce the size of the chronik-agora image

Summary:
The current container is based off the bitcoin-abc-dev image which is very big. Instead we can copy the binaries to a fresh minimal debian and just install the required dependencies.

This brings the image size from ~11.8GB down to ~173MB.

Test Plan:

docker build -t agora .
docker run agora:latest

Reviewers: #bitcoin_abc, bytesofman

Reviewed By: #bitcoin_abc, bytesofman

Subscribers: bytesofman

Differential Revision: https://reviews.bitcoinabc.org/D17491