Re-optimize filetype and category icons

core/img/actions/edit.svg

core/img/categories/auth.svg

core/img/categories/bundles.svg

core/img/categories/customization.svg

core/img/categories/files.svg

core/img/categories/integration.svg

core/img/categories/monitoring.svg

core/img/categories/multimedia.svg

core/img/categories/office.svg

core/img/categories/organization.svg

core/img/categories/social.svg

core/img/filetypes/application-pdf.svg

core/img/filetypes/application.svg

core/img/filetypes/audio.svg

core/img/filetypes/file.svg

core/img/filetypes/folder-drag-accept.svg

core/img/filetypes/folder-external.svg

core/img/filetypes/folder-public.svg

core/img/filetypes/folder-shared.svg

core/img/filetypes/folder-starred.svg