[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_alloc.go

@@ -0,0 +1,19 @@
+//go:build !(linux || darwin) || sqlite3_flock || sqlite3_nosys
+
+package vfs
+
+import (
+	"io"
+	"os"
+)
+
+func osAllocate(file *os.File, size int64) error {
+	off, err := file.Seek(0, io.SeekEnd)
+	if err != nil {
+		return err
+	}
+	if size <= off {
+		return nil
+	}
+	return file.Truncate(size)
+}