Openbrush Grant Application from Supercolony (w3f#497)

* Openbrush Grant Application from Supercolony

* Move some tasks from milestone 3 to milestone 2. Removed money for first milestone. Updated description of Grant and roadmap.

* Update openbrush.md

* Update openbrush.md

* Moved milestone to current scope with zero cost.

* Update openbrush.md

* Update applications/openbrush.md

Co-authored-by: Aleixo Sánchez <15819210+alxs@users.noreply.github.com>

* Moved Support fo additional contracts from milestone 3 to milestone 2.

* Update openbrush.md

Co-authored-by: xgreenx <xgreenx9999@gmail.com>
Co-authored-by: Aleixo Sánchez <15819210+alxs@users.noreply.github.com>