Implement basic city portal logic (and severely deabstract)

- Create a podman compose for Postgres
- Implement types and tables for urban data
- No longer use a Cargo workspace as there's no point currently
- Create query functionality (not mutation yet)

db/init.sql

@@ -0,0 +1,20 @@
+CREATE TABLE datasets (
+    id          SERIAL PRIMARY KEY,
+    name        TEXT NOT NULL,
+    description TEXT
+);
+
+CREATE TABLE locations (
+    id   SERIAL PRIMARY KEY,
+    name TEXT,
+    lat  DOUBLE PRECISION NOT NULL,
+    lon  DOUBLE PRECISION NOT NULL
+);
+
+CREATE TABLE records (
+    id          SERIAL PRIMARY KEY,
+    dataset_id  INTEGER NOT NULL REFERENCES datasets(id),
+    location_id INTEGER REFERENCES locations(id),
+    timestamp   TIMESTAMPTZ NOT NULL,
+    data        JSONB
+);