match espressif 3.0.3 Update

[Mandropil]

In the recent 3.0.x Board Library Update from Espressif the constants CAN_TX_ID and CAN_RX_IDX have been renamed to TWAI_RX_IDX/TWAI_TX_IDX and the define moved to #include "soc/gpio_sig_map.h". I adapted the source to match these changes.

I also put in a timing fix for 1Mbps BAud rate.