- changed and moved the main upload asset button to the left sidebar
above the categories for better visibility
- added individual upload buttons to all the category pages except
skybox - they open the same upload modal but sepcific to its category
only.
- flow update: once an upload succeeds the upload modal closes itself
and automatically reopens the asset modal to the mine tab and previously
uploaded category (so users don't have to have a hard time finding or
navigating to it)