[PM-21075] Initial database seeder (#5703)

Adds a database seeder which can be used standalone using a CLI for seeding your local development environment, or used in unit tests to seed complex scenarios.

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Co-authored-by: Robert Y <rkac@bitwarden.com>

util/Seeder/README.md

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+# Bitwarden Database Seeder
+
+A class library for generating and inserting test data.
+
+## Project Structure
+
+The project is organized into these main components:
+
+### Factories
+
+Factories are helper classes for creating domain entities and populating them with realistic data. This assist in
+decreasing the amount of boilerplate code needed to create test data in recipes.
+
+### Recipes
+
+Recipes are pre-defined data sets which can be run to generate and load data into the database. They often allow a allow
+for a few arguments to customize the data slightly. Recipes should be kept simple and focused on a single task. Default
+to creating more recipes rather than adding complexity to existing ones.