Support local deployment using SQLite database #1386
Description
Is your feature request related to a problem? Please describe.
Model Registry should support local lightweight deployments without having the need to configure and deploy either an external database. Since SQLite is a lightweight and simple to create database, it's an ideal candidate for such self contained deployments.
Supporting local deployment by simply running the model registry executable in a bare metal environment will allow users to experiment with Model Registry on their local machines. This is especially useful when using Model Registry to run local Experiments and Runs for various use cases like model training, model evaluations, RAG evaluation, etc.
Describe the solution you'd like
Support starting model registry with a SQLite DB configuration pointing to local file system where the database file should reside, or default to the current directory. Model Registry service should startup and create the database or reload an existing SQLite database file.
Describe alternatives you've considered
There are other lightweight databases like DuckDB, but SQLite seems to be the most popular among them. But, since MLMD also supports SQLite, it will be easier to use it's SQLite schema as a starting point for the embedmd store.
Additional context
The ability to create local self contained model registry instances will allow users to test and use model registry APIs and features without needing to deploy it in a Kubernetes cluster.