documents and simplifies how .env and .user-groups are passed to the images

app/example.user-groups.yaml

@@ -1,18 +0,0 @@
-# email-level group access
-users:
-  email1@example.com:
-    - group1
-    - group2
-  email2@example.com:
-    - group2
-  email3@example-no-group.com:
-
-# domain-level group access (taken from the emails)
-domains:
-  example.com:
-    - group3
-
-orchestrators:
-  group1: secrets/orchestration-group1.yaml
-  group2: secrets/orchestration-group2.yaml
-  default: secrets/orchestration-default.yaml

app/user-groups.example.yaml

@@ -1,62 +0,0 @@
-# NOTE: all emails should be lower-cased
-users:
-  user01@example.com:
-    - group1
-  user02@example.com:
-    - group2
-  user03@example.com:
-    - group1
-    - group2
-
-domains:
-  example.com:
-    - group-for-friends
-  gmail-example.com:
-    - group1
-
-
-groups:
-  group1:
-    description: "Group 1 which can do everything, no limits"
-    orchestrator: secrets/orchestration.group1.yaml
-    orchestrator_sheet: secrets/orchestration.group1-sheet.yaml
-    permissions:
-      read: ["all"]
-      archive_url: true
-      archive_sheet: true
-      sheet_frequency: ["hourly", "daily"]
-      max_sheets: -1
-      max_archive_lifespan_months: -1
-      max_monthly_urls: -1
-      max_monthly_mbs: -1
-      manually_trigger_sheet: true
-  group2:
-    description: "Group that can only archive URLs, not sheets, they can search their own group and group-for-friends archives."
-    orchestrator: secrets/orchestration.group2.yaml
-    orchestrator_sheet: secrets/orchestration-group2-sheet.yaml
-    permissions:
-      read: ["group2", "group-for-friends"]
-      archive_url: true
-      max_archive_lifespan_months: 12
-      max_monthly_urls: 100
-      max_monthly_mbs: 1000
-  group-for-friends:
-    description: "Friends can have one sheet only which archives once a day"
-    orchestrator: secrets/orchestration.friends.yaml
-    orchestrator_sheet: secrets/orchestration.friends-sheet.yaml
-    permissions:
-      read: ["friends-1"]
-      archive_sheet: true
-      sheet_frequency: ["daily"]
-      max_sheets: 1
-      max_archive_lifespan_months: 12
-      max_monthly_urls: 1000
-      max_monthly_mbs: 1000
-  default:
-    description: "Public access, can only search public archives"
-    orchestrator: secrets/orchestration-default.yaml
-    orchestrator_sheet: secrets/orchestration-default.yaml
-    permissions:
-      read: ["default"]
-      read_public: true
-