Add run control on non-numeric values

As a user I would like an intuitive way to set run control on enum/boolean values e.g. the shutter status. Currently they can set runcontrol on these as the underlying enum PV can be treated as a number (e.g. See run control settings in https://github.com/ISISComputingGroup/ibex_user_manual/wiki/CreateandManageConfigurations#blocks-tab) but this is not obvious to a user