platform: Add IHP SG13CMOS5L

Add IHP's SG13CMOS5L PDK.

This technology is almost identical to SG13G2, but is missing
the HBTs and has only 5 metal layers.
It's missing Metal5 and TopMetal2 for cheaper and faster
production runs.

Signed-off-by: Daniel Schultz <dnltz@aesc-silicon.de>

Author: dnltz

.gitignore

@@ -57,6 +57,7 @@ flow/*.opennet
 flow/platforms/*
 !flow/platforms/asap7
 !flow/platforms/ihp-sg13g2
+!flow/platforms/ihp-sg13cmos5l
 !flow/platforms/nangate45
 !flow/platforms/sky130hd
 !flow/platforms/sky130hs