Amend all text strings in en locales to use sentence case

Changelog.md

config/locales/diaspora/en.yml

config/locales/javascript/javascript.en.yml

features/desktop/connects_users.feature

features/desktop/follows_tags.feature

features/desktop/manages_aspects.feature

features/desktop/oembed.feature

features/desktop/posts_from_main_page.feature

features/desktop/signs_up.feature

features/desktop/single_post_view_moderation.feature

features/desktop/stops_following_users.feature

features/mobile/activity_stream.feature

features/mobile/drawer.feature

features/mobile/reactions.feature

features/mobile/reshare.feature

features/step_definitions/aspects_steps.rb

spec/javascripts/app/views/aspects_dropdown_view_spec.js