Add "install relevant plugins" to README

[mediapathic]

I've just opened this and immediately saw that Dashboard requires dataview and tasks to function. You may mention this elsewhere, but (related but different issue) in my case at least, "the first note you see" for me translates to Dashboard.

There may be other plugins required I haven't discovered yet, I let this issue stand as a placeholder for those if they exist.

[uwidev]

You're right. I didn't forgot git ignores folders that start with a period. I will push them immediately. Thank you for bringing this to my attention!