Blender Git Loki

GPencil: Draw Mode menu update

- Rename menu 'Stroke' to 'Draw': the menu includes not only strokes related things and the name follows the usage in other paint modes in Blender.
- Remove duplicate animation operators.
- Menu updates to include clean up and layers operators that don't need previous selection.

{F7705120}

Reviewers: antoniov, pepeland, billreynish

Tags: #bf_blender, #grease_pencil

Differential Revision: https://developer.blender.org/D5599