Docs: Create initial documentation

[bmtcril]

For v1 we want to create the following documents:

• Docs: How-to - Use Preset as a Superset backend #77
• Docs: How-to - Scaling #78
• Docs: How-to - Scaling - Superset #79
• Docs: How-to - Scaling - ClickHouse #80
• Docs: How-to - Scaling - Ralph #81
• Docs: How-to - Scaling - Vector #82
• Docs: How-to - Running without Tutor #83
• Docs: Backup and Restore ClickHouse #101
• Docs: Create a developer landing page for Aspects / Analytics #103
• Docs: How-to handle PII #108
• Docs: Update ADRs #61
• Docs: Concepts - dbt #68
• Docs: How-to - Dbt packages #73
• Docs: How-to - xAPI Transforms #75
• Docs: Update Readme #58
• Docs: Quick starts - Ralph #60
• Docs: Quick starts - Vector #59
• Docs: Concepts - xAPI #62
• Docs: Concepts - Tracking logs #63
• Docs: Concepts - Pipelines #64
• Docs: Concepts - Ralph #65
• Docs: Concepts - Vector #66
• Docs: Concepts - ClickHouse #67
• Docs: Concepts - Superset #69
• Docs: Concepts - Authentication / Permissions #70
• Docs: How-to - Changing the actor identifier #71
• Docs: How-to - Extending #72
• Docs: How-to - Custom Superset Dashboards #74
• Docs: How-to - Use ClickHouse Cloud or other cluster as a backend #76
• Docs: How-to - Backfill old or missing data #84