Add metagenome and markers upload modal (or buttons or card, etc.)

[evanroyrees]

• Implement ability to upload metagenome annotations (together and/or separately)
• Implement ability to upload annotations corresponding to searched marker set(s)
• Component to group/display upload components (e.g. buttons w/modal or card etc.)

In regards to the last point, we will need to determine what interface feels most natural to the end user. (:raised_hands: hurrah :raised_hands: for the guinea pigs :wave:)

• dcc.Upload(...) component
• dbc.Modal(...) component
• dbc.Card(...) component

.... We could also add these into the offcanvas