Randomize full MAC address

_Originally created by @anon62 on _#7038 (Redmine)

We now want to enable users to randomize the OUI part of the MAC address too.

To Do

• Verify that the proposal on #7038 (comment 196434) matches what Android does
• Implement the same MAC randomization as Android: #7038 (comment 196434)
• Update our design doc: #7038 (comment 214444)

What others do

• Windows 10-11 (random hardware addresses): https://support.microsoft.com/en-us/windows/how-to-use-random-hardware-addresses-in-windows-ac58de34-35fc-31ff-c650-823fc48eb1bc
• iPhone IOS (private Wi-Fi addresses): https://support.apple.com/en-us/102509
• Android: https://source.android.com/docs/core/connect/wifi-mac-randomization-behavior
  • example of how we could implement this: https://lists.autistici.org/message/20231210.232853.44a8aff6.en.html