Add hazard type sidebar filter

[lydiascarf]

posting this in case you want to merge it before the workshop! @matamadio

i wasn't sure i understood the motivation behind including all exposure datasets so i just wanted to explain how you could tweak this to work in a couple different ways:

• if you want to include all exposure datasets when hazard type is selected and have the badge count of each hazard type filter option's reflect this combined number, leave it as is
• if you want each hazard type filter option's badge count to reflect only the number of datasets with that hazard type, as opposed to that number + all of the exposure datasets, you would just need to remove ,...exposureDatasets from here and rebuild with npm run build
• if you decide you want to exclude all the exposure datasets when hazard type is selected, just drop dataset.category.includes('Exposure') || from here and rebuild with npm run build

good luck!

[matamadio]

Picked the second option: each hazard type filter option's badge reflects only the number of datasets with that hazard type, as opposed to that number + all of the exposure datasets.
I made the specified edits and forced rebuild, but it seems the filter number still shows the sum of datasets.