feat: all betterstack ip ranges and useragent (#16)

ref: https://betterstack.com/docs/uptime/frequently-asked-questions/#what-ips-does-uptime-use

I believe this is how you do it. Will test later on. Unfortunately their playwrite contains a generic user agent...

Co-authored-by: WeebDataHoarder <weebdatahoarder@noreply.gammaspectra.live>
Reviewed-on: https://git.gammaspectra.live/git/go-away/pulls/16
Co-authored-by: pwgen2155 <pwgen2155@noreply.gammaspectra.live>
Co-committed-by: pwgen2155 <pwgen2155@noreply.gammaspectra.live>

examples/snippets/bot-betterstack.yml

@@ -0,0 +1,8 @@
+networks:
+  betterstack:
+    - url: https://uptime.betterstack.com/ips-by-cluster.json
+      jq-path: '.[] | .[]'
+
+conditions:
+  is-bot-betterstack:
+      - &is-bot-betterstack '((userAgent.startsWith("Better Stack Better Uptime Bot") || userAgent.startsWith("Better Uptime Bot") || userAgent == "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/127.0.6533.17 Safari/537.36")) && remoteAddress.network("betterstack")'