XMas-Day-3: added Rotator block fixed frequency shifter

[RalphSteinhagen]

On the third day of Christmas 🎄 👼 3️⃣ 🎄 , my code base gave to me...

A Rotator block i.e fixed frequency shifter

• Introduce Rotator block that increments the phase before rotating each sample.
• handles angle wrapping to keep accumulated_phase in [0, 2π).

for more info see here.

Some visual unit-test examples:

[drslebedev]

Thanks a lot for the PR.

The new Rotator block and its unit tests look good and appear functionally correct.

There are a few minor issues worth addressing but PR can be also merged as is.

[RalphSteinhagen]

@drslebedev thanks for your feedback. I incorporated your comments and squash-merged them.

[sonarqubecloud]

Quality Gate failed

Failed conditions
53.8% Coverage on New Code (required ≥ 80%)

See analysis details on SonarQube Cloud