revert doc changes to GPIO & SPI classes about porting to platforms

This release basically reverts 1.3.10rc6 doc updates

hosting updated docs for PR review

properly documenting GPIO & SPI generic classes for porting information

hosting docs for PR review easability

doc'd macros for CRC, PALevel, & DataRate settings. Corresponding functions' docs use tables and link back to macros' docs.

testing gh-pages env

testing gh-pages env for different deployments based on different tagged commits

As for code state: all examples work on Linux (C++ & Python) & Arduino. IRQ_conf.py could use some tweaking and still need to adapt timingSearch3pin.ino for SpenceKonde ATTinyCore

• I also had an idea to use 1 file on Linux to #include cmd args parsing (& maybe an additional python script to import for cmd arg parsing)

hosting updated docs for preview

1.3.10rc3

final tweaks to IRQ examples; some doc updates