1. add hal and low-level layer for timer group
2. add callback functions to handle interrupt
3. add timer deinit function
4. add timer spinlock take function
New unity component can be used for testing other applications.
Upstream version of Unity is included as a submodule.
Utilities specific to ESP-IDF unit tests (partitions, leak checking
setup/teardown functions, etc) are kept only in unit-test-app.
Kconfig options are added to allow disabling certain Unity features.
This commit updates various test cases throughout esp-idf such that
the values used for timer divider pass the assertions in the timer component.
Timer divider values must be between 2 to 65536
