added display of a notification that the server is busy installing third-party software

- refactoring doInstallAction functions

client/server_scripts/check_server_is_busy.sh

@@ -0,0 +1,4 @@
+pm_apt="/usr/bin/apt-get";\
+if [[ -f "$pm_apt" ]]; then pm=$pm_apt; else exit; fi;\
+if [[ ! -f "/usr/bin/sudo" ]]; then $pm update -y -q; $pm install -y -q sudo; fi;\
+sudo fuser /var/lib/dpkg/lock-frontend