More robust handling of responses from NINA-FW

[jhodapp]

Description

This PR aims to create a more robust handling of replies & responses back from the NINA-FW on the ESP32 such that we're ready to implement a full handling of a response for issuing a ProtocolInterface::send_data(), after an HTTP GET, for example.

GitHub Issue: Related to #61

Changes

• Adds a max size check on creating a new NinaParam type and related unit tests
• Adds an architecture-independent CPU-friendly spin_loop() in wait_for_esp_ready() and wait_for_esp_ack()
• Ensures that we consume all 3 bytes when we encounter a ControlByte::Error from NINA-FW
• Breaks NinaProtocolHandler::receive() out into logical child functions to improve readability and maintainability

Testing Strategy

1. Run all example applications in cross/ on a target device
2. Run cargo test and ensure all tests pass

Concerns

None

[calebbourg]

Why was this necessary?
For my own education.

[jhodapp]

Otherwise Self won't have a known size and you get this error:

error[E0277]: the size for values of type `Self` cannot be known at compilation time
   --> esp32-wroom-rp/src/protocol.rs:58:27
    |
58  |     fn new(data: &str) -> Result<Self, Error>;
    |                           ^^^^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time
    |
note: required by a bound in `Result`
   --> /Users/jhodapp/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/core/src/result.rs:504:17
    |
504 | pub enum Result<T, E> {
    |                 ^ required by this bound in `Result`
help: consider further restricting `Self`
    |
58  |     fn new(data: &str) -> Result<Self, Error> where Self: Sized;
    |                                               +++++++++++++++++

[calebbourg]

Looks good!