UI release 1 - final items

Context

We are nearing the hand off date and there are some UI tweaks that would be ideal to make before the end of week

[ ] Use a select dropdown component https://v2.chakra-ui.com/docs/components/select instead of general input to be more intentional about the user interaction
[ ] Add drop shadow to the left panel to create visual separation between basemap and panel
[ ] Add units to the legend values
[ ] Reduce size of the buttons for 3D and draw panel + remove white box
[ ] Add link to GitHub repo on top nav (right)
[ ] Add scenario descriptions as option on legend. See final comment: https://github.com/developmentseed/tecnico-energy-app/issues/43
[ ] Add theme + description text to left panel based on user selection so that they know more clearly what they are seeing.