Update ESP32 RMT driver and managed code to latest API version

[AdrianSoundy]

Description

Currently the RMT code uses the legacy RMT API which is deprecated. This should be updated to the latest APi and include the new features.

• Stop warning error on ESP32 boot for RMT (legacy)
• Add the sync manager feature to synchronize the starting of multiple channels.
• Expose symbol encoder which can be used to speed up C# code or encoder can be called as part of rmt transmit.
• Update managed API to simplify the setting of RMT frequency (no need to know target RMT clock source/rate)
• Other manager API changes if required but try to keep backwards compatibility.

How to solve the problem

Update native and managed RMT code to use latest API.

Describe alternatives you've considered

No response

Aditional context

No response

[AdrianSoundy]

The new API has a number of underlying concept differences that will make C# code not backward compatible.

• The concept of channels has been removed and you now just create a new channel against gpio and it will internally give next available channel.

WIP