major refactor part 2: remove cold import, full sync, generalize node table

db/migrations/00018_create_ipfs_blocks_table.sql

@@ -0,0 +1,8 @@
+-- +goose Up
+CREATE TABLE IF NOT EXISTS public.blocks (
+  key TEXT UNIQUE NOT NULL,
+  data BYTEA NOT NULL
+);
+
+-- +goose Down
+DROP TABLE public.blocks;