Add Blur and Smudge Brush for texturing

[lucasmessias322]

IMPORTANT: Please remember to update plugin metadata in plugins.json along with the metadata in your plugin. Always increase the version number when submitting an update.

Please only update one plugin per pull-request (unless you are applying the same fix to multiple pull requests, and nothing else).

[lucasmessias322]

Add Blur and Smudge Brush for texturing

[JannisX11]

Please follow the instructions in README.md for adding your plugin, and ensure it passes the automatic validator.
In terms of functionality, the only issue seems to be that when first selecting one of the brushes, the Radius/Intensity/Distance sliders are empty and do not display a number.