feat: automatically discover inventory (#127)

## Fully automated inventory gathering now works!

Boot up harmony_inventory_agent with `cargo run -p harmony_inventory_agent`
Launch the DiscoverInventoryAgentScore , currently available this way :

`RUST_LOG=info cargo run -p example-cli -- -f Discover -y`

And you will have automatically all hosts saved to the database. Run `cargo sqlx setup` if you have not done it yet.

Co-authored-by: Ian Letourneau <ian@noma.to>
Reviewed-on: #127
Co-authored-by: Jean-Gabriel Gill-Couture <jg@nationtech.io>
Co-committed-by: Jean-Gabriel Gill-Couture <jg@nationtech.io>

migrations/20250830163356_Physical_hosts.sql

@@ -0,0 +1,8 @@
+-- Add migration script here
+CREATE TABLE IF NOT EXISTS physical_hosts (
+    version_id TEXT PRIMARY KEY NOT NULL,
+    id TEXT NOT NULL,
+    data JSON NOT NULL
+);
+CREATE INDEX IF NOT EXISTS idx_host_id_time
+ON physical_hosts (id, version_id DESC);