Remove the ESP-IDF from git submodules to avoid potential
duplicated repo clones on the user system. IDF HAL code is still
a dependency for Espressif port, therefore now the HAL code
reference needs to be passed by parameter when building.
The Espressif port was also updated to work with last v5.1 IDF
code.
Signed-off-by: Almir Okato <almir.okato@espressif.com>