Add esp32 support

[hippo5329]

These patches add basic esp32 support.

First, the imu libraries are replaced with i2cdev upstream to remove compilation errors and improve stability. Then the motor and encoder support for esp32 are added. last, the esp32 board support are added as a custom configuration.

No wifi support. Only serial micro-ROS transport is supported. But this should be enough for most applications, Additional configurations are reserved for future extensions.

Cheers, Thomas Chou

[hippo5329]

After these got merged, I will send PR for micro-ROS wifi transport support and pico port.

[grassjelly]

thanks @hippo5329

[hippo5329]

Thank you.