Add custom list views

[mildred]

Part of #798

Implementation:

• Add a CustomListView model
  • name: string
  • filter: JSON
  • groupName: string
• in sidebarConfig.ts, add those custom lists views to the sidebar config
• In ListView.vue
  • when a filter is defined, add a button to save the view
  • if the view is already a custom view, it will jsut save the view
  • if the view is not a custom view, ask for a view name and create the custom view
  • if the view is a custom view, add a button to remove the custom view and a way to rename it
  • custom view filters should not be marked implicit (in setFilter(filters, implicit))