server: setup with PG in Docker

[norwnd]

This describes how to set up DEX server on testnet with Postgres in Docker (managed by docker-compose). Just notes for myself.

Install Decred cli suite: https://docs.decred.org/wallets/cli/cli-installation/

Set up dcrwallet and copy rpc.cert into its cfg dir from dcrd cfg dir: https://docs.decred.org/wallets/cli/dcrwallet-setup/
Then configure legacy account public key: https://github.com/decred/dcrdex/wiki/Server-Installation#generate-a-dcrwallet-account-public-key (won't be using it, just for bypassing some legacy validation)

Set up DEX server configuration files (in .../Dcrdex cfg dir), use sample config files from this PR to get some working configuration (search by sample-):

• ethereum.conf that contains a bunch of Providers:

https://rpc.ankr.com/eth_goerli
https://goerli.infura.io/v3/461b0a1394a9420fab769fa4994de393

• markets.json, it will also require paths to dcrd (in .../Dcrdex cfg dir) and ethereum.conf config
• dcrdex.conf (set pgpass=dexpass https://github.com/decred/dcrdex/wiki/Server-Installation#generate-a-dcrwallet-account-public-key)

Run Postgres in Docker (it also will create dcrdex user and dcrdex_testnet DB):

make server_deps_up

Note, it will run with volume attached and managed by Docker (you can see it via docker volume ls | grep server_db) to persist server data between Postgres container restarts. Tip: use https://github.com/sosedoff/pgweb for easy access to DB data.

Run and sync (might take several hours) dcrd:

decred/dcrd --testnet --txindex

Build and run DEX server:

make server_build
make server_run

Use printed out URL to connect your dexc to this server:

127.0.0.1:7232

and rpc.cert from .../Dcrdex cfg dir.