There are multiple changes in this commit:
1. Unify the RISC-V and ULP-FSM code paths in esp32ulp_mapgen.py.
It seems that these were originally introduced because `nm` output
for the RISC-V case contained symbol sizes, while for the ULP-FSM
no symbol sizes were reported. This makes sense, because the
ULP-FSM object files are produced from assembly source, symbol
sizes have to be added manually using the .size directive.
In the case of RISC-V, the object files are built from C sources
and the sizes are automatically added by the compiler.
Now 'posix' output format is used for both RISC-V and ULP-FSM.
2. Move BASE_ADDR out of esp32ulp_mapgen.py. This now has to be passed
from CMake, which should make it easier to modify if a new chip
with a different RTC RAM base address is added.
3. Add C++ guards to the generated header file.
4. Switch from optparse to argparse for similarity with other IDF
tools.
5. Add type annotations.
