Improve display of element sections

[Eveliyse]

I was looking at using this plugin and ran across the same problem described in #330 (mainly I don't use the tasks but found the empty card to be taking up precious screen real estate). I set out to fix this problem for myself but thought it might be a good idea to contribute what I've done back to the codebase but as I was tidying up the code I realised that what I had implemented may not fit the current design philosophy.

I started changing/adding many things and eventually decided to pause and ask for clarification here!

Changes I've currently made:

• Added settings to toggle task and relationship card visibility for each element type
  • This is non-destructive in that no tasks/relationships are deleted (so they will still appear in searches)
• Made the attribute card not display for an element if it has no attributes to display
• Made the relationship card not display for an element if it has no relationships to display
• Added the ability to add a task via the options pane
• Made the task card not display for an element if it has no relationships to display

I think I am leaning towards removing the settings since just having the cards not display if they are empty already fix the "empty cards take up room" problem. I am happy to make different changes though if the path I've started down is the wrong one!