[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/tetratelabs/wazero/internal/sysfs/unlink.go

@@ -0,0 +1,17 @@
+//go:build !windows && !plan9 && !tinygo
+
+package sysfs
+
+import (
+	"syscall"
+
+	"github.com/tetratelabs/wazero/experimental/sys"
+)
+
+func unlink(name string) (errno sys.Errno) {
+	err := syscall.Unlink(name)
+	if errno = sys.UnwrapOSError(err); errno == sys.EPERM {
+		errno = sys.EISDIR
+	}
+	return errno
+}