These were the leftover tasks from #145

• Merge web watcher events into window events in the query? (to allow for classifying by url/domain)
• Category Tree: If a category has children, but also activity attributed directly to the parent that does not belong to a child, then create a "Other" child containing the activity.
• Should we have a way to filter on a specific event key? Right now the regexes are applied on every (string) data value. (feat: more categorization and support for select_keys #286)
• Add a way to show how/which events are (un)categorized
• Fix summary view to also use Vuex and all the new goodies
• Improve default categories (Improving the default categories #174)
• Link to docs and/or regex101, explaining how regular expressions work and how to write good categorization rules.