"ethcrawler trending" humbug token from env

This makes life easier when using it as a systemd service.

Also added systemd service and timer for trending addresses crawler.

crawlers/deploy/ethereum-trending.service

@@ -0,0 +1,11 @@
+[Unit]
+Description=Load trending Ethereum addresses to the database
+After=network.target
+
+[Service]
+Type=oneshot
+User=ubuntu
+Group=www-data
+WorkingDirectory=/home/ubuntu/moonstream/crawlers
+EnvironmentFile=/home/ubuntu/mooncrawl-secrets/app.env
+ExecStart=/usr/bin/bash -c '/home/ubuntu/mooncrawl-env/bin/python -m mooncrawl.ethcrawler trending -s $(date -u -d '-2 hours' +%Y%m%d-%H%MT%z) -e $(date -u +%Y%m%d-%H%MT%z)'

crawlers/deploy/ethereum-trending.timer

@@ -0,0 +1,9 @@
+[Unit]
+Description=Load trending Ethereum addresses to the database every 5 minutes
+
+[Timer]
+OnBootSec=10s
+OnUnitActiveSec=5m
+
+[Install]
+WantedBy=timers.target

crawlers/mooncrawl/ethcrawler.py

@@ -4,6 +4,7 @@ Moonstream crawlers CLI.
 import argparse
 from enum import Enum
 import json
+import os
 import sys
 import time
 from typing import Iterator, List
@@ -177,7 +178,10 @@ def ethcrawler_trending_handler(args: argparse.Namespace) -> None:
         include_end=args.include_end,
     )
     results = trending(date_range)
-    if args.humbug:
+    humbug_token = args.humbug
+    if humbug_token is None:
+        humbug_token = os.environ.get("MOONSTREAM_HUMBUG_TOKEN")
+    if humbug_token:
         opening_bracket = "[" if args.include_start else "("
         closing_bracket = "]" if args.include_end else ")"
         title = f"Ethereum trending addresses: {opening_bracket}{args.start}, {args.end}{closing_bracket}"
@@ -358,7 +362,11 @@ def main() -> None:
     parser_ethcrawler_trending.add_argument(
         "--humbug",
         default=None,
-        help="If you would like to write this data to a Moonstream journal, please provide a Humbug token for that here.",
+        help=(
+            "If you would like to write this data to a Moonstream journal, please provide a Humbug "
+            "token for that here. (This argument overrides any value set in the "
+            "MOONSTREAM_HUMBUG_TOKEN environment variable)"
+        ),
     )
     parser_ethcrawler_trending.add_argument(
         "-o",