wifi(implementation): Add unit test framework

We're going to add some non-trivial logic in wifi chip to handle
multiple chip configurations (to support devices with different
capabilities). So, adding a unit test framework in preparation
for testing those changes.

The mocks only mock legacy HAL methods which are in use during chip
configuration & interface creation/deletion.

Bug: 68775880
Test: Compiles
Change-Id: I8575df02f54656f77077d14ac9535ccc974bdff3