* Delete variants/nrf52840/diy/nrf52_promicro_diy_tcxo/Schematic_Pro-Micro_Pinouts.pdf
remove old file
* Add updated schematic
* Update GPS TX and RX pin definitions after swap
* Update GPS pin definitions and schematic link
Updated the schematic link to reflect GPS pin definition changes.
* Update to Pro-micro variants
Schematic updated
Xtal variant removed
Extra module added to list
Extra explanation added to readme.
* Fix markdown formatting in readme.md
* Fix formatting in readme.md for RF switch section
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Co-authored-by: Tom <116762865+Nestpebble@users.noreply.github.com>