Allow custom model upload

[jcabrero]

This involves allowing users to upload their models in a secure way.

How to:

• Allow for model uploads
  • Introduce secure model upload.
  • Encryption of the models including a potential key management.
  • Storage of models in S3.
• Model access control
  • This involves adding a layer of security to the database interaction.
  • If a user API key has uploaded the model or is within the allowlist of a model, then they can use it.
• Model inference and orchestration.
  • Assuming users upload their models to our platform: what is the way to have these models in memory?
  • Are there any caching priorities.

The above questions should be answered before finishing this PR

[jcabrero]

It is up to the node operator to decide what models can be uploaded for now.