Multiple partitions, one at a time.

Coped from SPIFFS implementation.
espressif/arduino-esp32@3cbfa2f#diff-d033864b5ea50ef1ee43c07dfc1ec7c828f4eff57dee791348fd66e6d588ac78
See LITTLEFS_test example

Detect the core and IDF revision during compile time.

Requesting acceptance by Arduino Library Manager. Tag v1.0 is for esp…

…32 core release 1.0.4