chore: update README.md and add ARCHITECTURE.md

[ChaoticTempest]

Long overdue, since our main page README was about mpc-recovery this whole time. Moved that to the mpc-recovery folder instead.

Also added ARCHITECTURE.md to explain chain-signatures

[ailisp]

Great update! It's very helpful to me

[github-actions]

Terraform Feature Environment Destroy (dev-627)

Terraform Initialization ⚙️success

Terraform Destroy success

Show Destroy Plan

No changes. No objects need to be destroyed.

Either you have not created any objects yet or the existing objects were
already deleted outside of Terraform.

Destroy complete! Resources: 0 destroyed.

Pusher: @ChaoticTempest, Action: pull_request, Working Directory: ``, Workflow: Terraform Feature Env (Destroy)

[volovyks]

Nice!