feat: add image models

migrations/2025-01-16-195902_images/down.sql

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+drop table images;

migrations/2025-01-16-195902_images/up.sql

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+create table images (
+    id integer primary key not null,
+    plant_id integer not null
+        references plants (id)
+        -- Keep entries in the database so the files can be removed later
+        on delete set null,
+    date_taken date not null,
+    note text
+);