[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/vfs/os_std_mode.go

@@ -0,0 +1,14 @@
+//go:build !unix || sqlite3_nosys
+
+package vfs
+
+import "os"
+
+func osSetMode(file *os.File, modeof string) error {
+	fi, err := os.Stat(modeof)
+	if err != nil {
+		return err
+	}
+	file.Chmod(fi.Mode())
+	return nil
+}