[PM-17353] feat: allow configuring GlobalSettings via KeyPerFile configuration provider

[mu88]

With this change, one can make use of Docker Compose Secrets.

🎟️ Tracking

https://community.bitwarden.com/t/add-support-for-docker-secrets-to-self-host-project/69705/3

📔 Objective

Since there was/is no vital conversion in the corresponding Discourse thread, I thought I give it a shot and propose my desired change as a PR. Please bear with me if this violates one of your processes - I'm happy to learn and adapt 🙂

As written in the corresponding thread, it would be great if one could make use of Docker Compose Secrets, especially for passing installation ID and key. Of course, following the common _FILE suffix convention would be the very best solution. But as a first step in this direction, I decided to add the Key-per-file configuration provider so that one can start a Docker stack like this:

services:
  bitwarden:
    image: bitwarden/self-host:beta
    volumes:
      - ./data:/etc/bitwarden
    ports:
      - "8080:8080"
    environment:
      - BW_ENABLE_SSL=false
      - BW_DB_PROVIDER=sqlite
      - BW_DOMAIN=my.app.domain
      - GlobalSettings__Installation__FileConfigDirectory=/run/secrets/
    secrets:
      - GlobalSettings__Installation__Id
      - GlobalSettings__Installation__Key
secrets:
  GlobalSettings__Installation__Id:
    file: ./installation_id.txt
  GlobalSettings__Installation__Key:
    file: ./installation_key.txt

This way, .NET will automatically pick up all files within the config directory /run/secrets (which is the default of Docker Compose, see here) and map them convention-based to the corresponding config object.

📸 Screenshots

Not applicable since there is no UI change.

⏰ Reminders before review

• Contributor guidelines followed
• All formatters and local linters executed and passed
• Written new unit and / or integration tests where applicable
• Protected functional changes with optionality (feature flags)
• Used internationalization (i18n) for all UI strings
• CI builds passed
• Communicated to DevOps any deployment requirements
• Updated any necessary documentation (Confluence, contributing docs) or informed the documentation team

🦮 Reviewer guidelines

• 👍 (:+1:) or similar for great changes
• 📝 (:memo:) or ℹ️ (:information_source:) for notes or general info
• ❓ (:question:) for questions
• 🤔 (:thinking:) or 💭 (:thought_balloon:) for more open inquiry that's not quite a confirmed issue and could potentially benefit from discussion
• 🎨 (:art:) for suggestions / improvements
• ❌ (:x:) or ⚠️ (:warning:) for more significant problems or concerns needing attention
• 🌱 (:seedling:) or ♻️ (:recycle:) for future improvements or indications of technical debt
• ⛏ (:pick:) for minor or nitpick changes

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[bitwarden-bot]

Thank you for your contribution! We've added this to our internal Community PR board for review.
ID: PM-17353
Link: https://bitwarden.atlassian.net/browse/PM-17353

Details on our contribution process can be found here: https://contributing.bitwarden.com/contributing/pull-requests/community-pr-process.