Power optimization - Improve SPI sleep mode

Ensure that all pins are set to their default configuration during sleep mode.
Disable the workaround for FTPAN58 (SPI freezes when transfering a single byte) at the end of the transfer. This disables the resources needed for the workaround.
Those changes reduce the power usage by 430-490µA.

src/drivers/SpiNorFlash.cpp

@@ -10,6 +10,7 @@ SpiNorFlash::SpiNorFlash(Spi& spi) : spi {spi} {
 }
 
 void SpiNorFlash::Init() {
+  spi.Init();
   device_id = ReadIdentificaion();
   NRF_LOG_INFO("[SpiNorFlash] Manufacturer : %d, Memory type : %d, memory density : %d",
                device_id.manufacturer,
@@ -23,10 +24,12 @@ void SpiNorFlash::Uninit() {
 void SpiNorFlash::Sleep() {
   auto cmd = static_cast<uint8_t>(Commands::DeepPowerDown);
   spi.Write(&cmd, sizeof(uint8_t));
+  spi.Sleep();
   NRF_LOG_INFO("[SpiNorFlash] Sleep")
 }
 
 void SpiNorFlash::Wakeup() {
+  spi.Wakeup();
   // send Commands::ReleaseFromDeepPowerDown then 3 dummy bytes before reading Device ID
   static constexpr uint8_t cmdSize = 4;
   uint8_t cmd[cmdSize] = {static_cast<uint8_t>(Commands::ReleaseFromDeepPowerDown), 0x01, 0x02, 0x03};