NRFX SPI bus implementation for Sidewalk

[MarGasiorek]

SPI bus implementation based on the NRFX for Sidewalk.

CI parameters

Github_actions:
  #(branch, hash, pull/XXX/head)
  NRF_revision: main

  # Do not change after creating PR
  Create_NRF_PR: false
Jenkins:
  test-sdk-sidewalk: master

Description

Generally this PR helps to improve SPI communication (for nRF52) thus FSK experience as well.
JIRA ticket: KRKNWK-19259

Self review

• There is no commented code.
• There are no TODO/FIXME comments without associated issue ticket.
• Commits are properly organized.
• Change has been tested.
• Tests were updated (if applicable).

[github-actions]

Sample		diff	used	total
nrf52840dk/nrf52840:sample.sidewalk.demo	RAM	-160 B	118.66 KB	0 B
	ROM	-4.81 KB	431.69 KB	0 B
nrf52840dk/nrf52840:sample.sidewalk.dut	RAM	-160 B	142.24 KB	0 B
	ROM	-4.89 KB	495.96 KB	0 B
nrf52840dk/nrf52840:sample.sidewalk.dut.no_secure	RAM	-160 B	142.22 KB	0 B
	ROM	-4.89 KB	487.49 KB	0 B
nrf52840dk/nrf52840:sample.sidewalk.hello	RAM	-160 B	119.83 KB	0 B
	ROM	-4.81 KB	446.38 KB	0 B
nrf52840dk/nrf52840:sample.sidewalk.hello.release	RAM	-160 B	103.68 KB	0 B
	ROM	-3.63 KB	363.95 KB	0 B

[ktaborowski]

code looks good, please make sure there is no regression

[totyz]

test PASSED