build/sqlc: implement simple sqlc/bindata rules

This is a first pass at implementing rules to generate sqlc stubs from
.sql files and embed relevant migration files into bindata.

This is not yet used. The Go API is subject to change - especially the
way migrations are laid out in the generated package will probably
change.

Change-Id: I0873031603957a176ad4664c3b10768b791e0dd5
Reviewed-on: https://review.monogon.dev/c/monogon/+/884
Tested-by: Jenkins CI
Reviewed-by: Leopold Schabel <leo@monogon.tech>
diff --git a/build/sqlc/tool-dep/gomod-generated-placeholder.go b/build/sqlc/tool-dep/gomod-generated-placeholder.go
index 924235c..7db97d2 100644
--- a/build/sqlc/tool-dep/gomod-generated-placeholder.go
+++ b/build/sqlc/tool-dep/gomod-generated-placeholder.go
@@ -6,6 +6,7 @@
 package main
 
 import (
+	_ "github.com/kevinburke/go-bindata"
 	_ "github.com/kyleconroy/sqlc/pkg/cli"
 )