added git submodules for dependencies/openlane_src, deps/timing-scripts and mgmt_core_wrapper

.gitmodules

diff --git a/.gitmodules b/.gitmodules
index 5bdfdae..5b36ba1 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,3 +1,12 @@
 [submodule "caravel"]
 	path = caravel
 	url = https://github.com/efabless/caravel
+[submodule "mgmt_core_wrapper"]
+	path = mgmt_core_wrapper
+	url = https://github.com/efabless/caravel_mgmt_soc_litex
+[submodule "dependencies/openlane_src"]
+	path = dependencies/openlane_src
+	url = https://github.com/The-OpenROAD-Project/OpenLane
+[submodule "deps/timing-scripts"]
+	path = deps/timing-scripts
+	url = https://github.com/efabless/timing-scripts.git

mgmt_core_wrapper

diff --git a/mgmt_core_wrapper b/mgmt_core_wrapper
new file mode 160000
index 0000000..453e4cc
--- /dev/null
+++ b/mgmt_core_wrapper
@@ -0,0 +1 @@
+Subproject commit 453e4cca7d165db005492cd1a93a3a8aed710e2b