Added:
* set a secure version in app/bootloader.
* description anti-rollback to ota part
* emulate the secure_version write and read operations
* efuse_em partition.
* a description about a rollback for native_ota_example.
Closes: TW26335
* App access functions are all flash encryption-aware
* Documentation for flash encryption
* Partition read/write is flash aware
* New encrypted write function
