Initial Docker support

[knorrium]

% docker-compose up
[+] Running 1/0
 ✔ Container electrs-mempool-electrs-1  Created                                                                                 0.0s
Attaching to electrs-mempool-electrs-1
electrs-mempool-electrs-1  | Config { log: StdErrLog { verbosity: Error, quiet: false, show_level: true, timestamp: Off, modules: [], writer: "stderr", color_choice: Never }, network_type: Bitcoin, db_path: "
electrs-mempool-electrs-1  | /electrs/mainnet", daemon_dir: "/root/.bitcoin", blocks_dir: "/root/.bitcoin/blocks", daemon_rpc_addr: 127.0.0.1:8332, cookie: Some("mempool:mempool")
electrs-mempool-electrs-1  | , electrum_rpc_addr: 127.0.0.1:50001, http_addr: 127.0.0.1:3000, http_socket_file: None, monitoring_addr: 127.0.0.1:4224, jsonrpc_import: false, light_mode: false, address_search: true, index_unspendables: false, cors: Some("*"), precache_scripts: None, utxos_limit: 500, electrum_txs_limit: 500, electrum_banner: "Welcome to mempool-electrs 3.0.0-dev", mempool_backlog_stats_ttl: 10, mempool_recent_txs_size: 10, rest_default_block_limit: 10, rest_default_chain_txs_per_page: 25, rest_default_max_mempool_txs
electrs-mempool-electrs-1  | : 50 }

[junderw]

LGTM

[softsimon]

utACK