Add troubleshooting guide

Also make sure that the gadget installer and other docs are included in
the tarball installation.

make_package

@@ -16,13 +16,20 @@ mkdir -p ${PACK}
 pushd ${PACK}
   mkdir -p vimspector/opt/vimspector
   pushd vimspector/opt/vimspector
-    for d in autoload plugin python3 vendor doc; do
+    for d in autoload plugin python3 vendor doc support; do
       if [[ -d ${ROOT}/$d ]]; then
         cp -r ${ROOT}/$d .
       fi
     done
     mkdir -p gadgets
     cp -r ${ROOT}/gadgets/${OS} gadgets/
+    for f in install_gadget.py \
+             CODE_OF_CONDUCT.md \
+             CONTRIBUTING.md \
+             LICENCE \
+             README.md; do
+      cp ${ROOT}/${f} .
+    done
   popd
 popd