scripts: size_report: rework to use pyelftools...

...instead of GNU binutils to extract DWARF information.
This is now a bit more portable across OS and toolchain.
One bouns is that this nows with on qemu_x86_64.

A few differences are:
() z_mrsh_* which are aliases to handler_no_syscalls() are now
   dropped as they are mapped to the same address, so that they
   are not counted multiple times.
() Static functions and variables with same names should now be
   attributed to the correct source files instead of being
   accumulated into the same symbol of one file (e.g. multiple
   thread_entry() in kernel tests).
() The totals for ROM and RAM are calculated from the
   corresponding sections. Previous script includes the debug
   sections as total ROM size which is not entirely correct.

Fixes #22996

Signed-off-by: Daniel Leung <daniel.leung@intel.com>