Remove Cadence & Synopsys plugins (#1410)

* remove Cadence & Synopsys plugins from docs and scripts

* update conda-locks

scripts/init-vlsi.sh

@@ -12,10 +12,6 @@ fi
 
 # Initialize HAMMER CAD-plugins
 if [[ $1 != *openroad* ]] && [[ $2 != *openroad* ]]; then
-    git submodule update --init --recursive vlsi/hammer-cadence-plugins
-    pip install -e vlsi/hammer-cadence-plugins
-    git submodule update --init --recursive vlsi/hammer-synopsys-plugins
-    pip install -e vlsi/hammer-synopsys-plugins
     git submodule update --init --recursive vlsi/hammer-mentor-plugins
     pip install -e vlsi/hammer-mentor-plugins
 fi