Post-grand-merge tasks

This is the list of tasks to be done after !78 (merged) is merged (copied from there):

• Change coverage badge to point to coverage/index.html
• Move atk bugs to at-spi2-core
• Move at-spi2-atk bugs to at-spi2-core
• Review all merge requests for atk, merge them or close them.
• Review all merge requests for at-spi2-atk, merge them or close them.
• Archive atk? Maybe leave it up for old-stable branches?
• Archive at-spi2-atk? Maybe leave it up for old-stable branches?
• Notify release team of combined modules.
• Notify distributor-list and discourse about combined modules - https://discourse.gnome.org/t/atk-and-at-spi2-atk-merged-into-at-spi2-core/10032