[experiment] add alternative wasm sqlite3 implementation available via build-tag (#2863)

This allows for building GoToSocial with [SQLite transpiled to WASM](https://github.com/ncruces/go-sqlite3) and accessed through [Wazero](https://wazero.io/).

vendor/github.com/ncruces/go-sqlite3/pointer.go

@@ -0,0 +1,12 @@
+package sqlite3
+
+import "github.com/ncruces/go-sqlite3/internal/util"
+
+// Pointer returns a pointer to a value that can be used as an argument to
+// [database/sql.DB.Exec] and similar methods.
+// Pointer should NOT be used with [BindPointer] or [ResultPointer].
+//
+// https://sqlite.org/bindptr.html
+func Pointer[T any](value T) any {
+	return util.Pointer[T]{Value: value}
+}