profiling: Add perf tool

Add profiling subsystem.

Add perf util based on periodic stack unwinding. Perf from Linux
was taken as a reference.

The operation of module is based on frame pointer usage and saving
registers during interruption handling.
The unwinding function stay in timer as expiry functioin so is called
during interruption handling. Thus the function have access to saved
registers (program counter and frame pointer in particular) of the current
thread and use it to unwind the thread stack.
Timer starting and results printing function are made as shell commands
for conveniency.

Originally-by: Yonatan Goldschmidt <yon.goldschmidt@gmail.com>
Signed-off-by: Mikhail Kushnerov <m.kushnerov@yadro.com>