Initial extension set up

* Extension help can be found in the "Help" section in Ghidra
  * Extension build script, LICENSE and README added

README.md

@@ -0,0 +1,27 @@
+# GhidRust: Rust binary analysis extension
+
+## Building
+
+There is a build script provided (`build.sh`) which can build and install the extension.
+
+```
+$ ./build.sh -h
+GhidRust install script
+Usage: build.sh [-i | --install] -g GHIDRA_PATH
+
+        -i | --install           Install the extension
+        -g | --ghidra            Path to Ghidra installation (usually /opt/ghidra)
+        -h | --help              Show usage/help
+```
+
+You can build the extension using the following command.
+
+```
+$ ./build.sh -g <GHIDRA_INSTALL_DIR>
+```
+
+You can install it using the install flag as follows.
+
+```
+./build.sh -ig <GHIDRA_INSTALL_DIR>
+```