This commit updates `VerifyOrQuit()` and `SuccessOrQuit()` macros to
include the failed condition in the error message that is printed on
a failure (in addition to function name and line number where the
error happened). This commit also changes the second parameter
(`aMessage`) to in these macros to be optional.
This commit also updates unit tests to remove the second `aMessage`
string in cases where the failure can be inferred from the condition
itself.
This commit adds a `Pskc` as a wrapper over `otPskc` and also
renames all the uses of `PSK` into `Psk` to follow our variable
and type naming convention which treats an acronym as a whole
word.
Abtin Keshavarzian