Move quic::QuicEndian to quiche::QuicheEndian This change will enable us to reuse the endian library in new third_party repos without introducing a dependency on //third_party/quic. gfe-relnote: Refactor of QUIC Endian library PiperOrigin-RevId: 281406510 Change-Id: If1b72425a799bad7469281f32a12d6630fe787c4