sql: remove distributor stock

schema.sql

@@ -83,14 +83,6 @@ CREATE TABLE IF NOT EXISTS distribution (
 	FOREIGN KEY (distributor) REFERENCES distributor (id)
 );
 
--- part stock at a distributor
-CREATE TABLE IF NOT EXISTS stock (
-	id INTEGER AUTO_INCREMENT PRIMARY KEY, -- index
-	distribution INTEGER NOT NULL, -- the part
-	stock INTEGER NOT NULL,
-	FOREIGN KEY (distribution) REFERENCES distribution (id)
-);
-
 CREATE TABLE IF NOT EXISTS document (
 	id INTEGER AUTO_INCREMENT PRIMARY KEY, -- index
 	type TEXT -- document type