Add conversation-footing to make conversations collapsible from bottom
requested to merge nekojanai/pleroma-fe:feat/collapse-conversations-from-bottom-or-something into develop
Conversations/Threads should be collapsible from the bottom of a conversation/thread, this adds a conversation-footing which is a carbon copy of conversation-heading with the exception of a panel-footing css class instead of a panel-heading css class, this class inherits everything from panel-heading and overwrites border-radius to accommodate for the inverted application of the radius