Show authorization rule access type in the rule list as a new column

[ryannewington]

Coming from idea #76 by @sylwester-majcher

We should add a new column to the authorization rules list that shows what type of access is granted by the rule.

This is really expensive to work out in real time, so I think we need to pre-calcuate and store it as a 'hint' before it gets rendered. This could be metadata in the config file itself, or perhaps generated by the UI app when the config file is first opened.