Add Bloom Host (#672)

## Description

This PR add the Bloom Host icon to ente auth. Bloom Host is a dedicated
Minecraft hosting, VPS and a bare metal server hosting company.

auth/assets/custom-icons/_data/custom-icons.json

@@ -30,6 +30,10 @@
     {
       "title": "Bitwarden"
     },
+    {
+      "title": "Bloom Host",
+      "slug": "bloom_host"
+    },
     {
       "title": "BorgBase",
       "altNames": ["borg"],