feat(example): encode audio with Opus

[Marc-Andre Lureau (elmarco)]

Demonstrates Opus audio codec support (and also fixes sine wave phase)

[Benoît Cortier (CBenoit)]

Thank you!

[Benoît Cortier (CBenoit)]

suggestion: My typical suggestion for this kind of code is to go with the bytemuck crate instead of writing the unsafe code each time; or to make a copy of the data. The latter solution is obviously less performant, but does not require an additional dependency. (I’m almost sure bytemuck is already to be found somewhere in our stack though.)

Otherwise, you need to ensure the alignment is correct and provide a convincing safety comment describing how the code is correct.

   error: unsafe block missing a safety comment
     --> crates/ironrdp/examples/server.rs:331:33
      |
  331 |                     let input = unsafe { slice::from_raw_parts(data.as_ptr() as *const i16, data.len() / 2) };
      |                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
      |
      = help: consider adding a safety comment on the preceding line
      = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#undocumented_unsafe_blocks
      = note: `-D clippy::undocumented-unsafe-blocks` implied by `-D warnings`
      = help: to override `-D warnings` add `#[allow(clippy::undocumented_unsafe_blocks)]`
  
  error: casting from `*const u8` to a more-strictly-aligned pointer (`*const i16`) (1 < 2 bytes)
     --> crates/ironrdp/examples/server.rs:331:64
      |
  331 |                     let input = unsafe { slice::from_raw_parts(data.as_ptr() as *const i16, data.len() / 2) };
      |                                                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^
      |
      = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#cast_ptr_alignment
      = note: `-D clippy::cast-ptr-alignment` implied by `-D warnings`
      = help: to override `-D warnings` add `#[allow(clippy::cast_ptr_alignment)]`
  
  error: could not compile `ironrdp` (example "server") due to 2 previous errors

[Benoît Cortier (CBenoit)]

Lints step is failed.