move load session stuff to session.c

merge update_cert and tofu_update into tofu_update_persist

merge tofu_add and save_cert into tofu_save

move bookmark_page off fs.c

generate session/history_file atomically if an i/o error occurs while writing those files, they may end up being corrupted or truncated. Use the approach already used for tofu, write a temp file and rename(2) it to the correct position.

merge the fs into the ui process The previous separation between the fs and ui process wasn't that good. The idea was to have a `ui' process tightly sandboxed, but it was a lie actually. `ui' was one imsg away from making internet connections and accessing data on the disk, so it wasn't really limited in (almost) any way. Furthermore, having to serialize data to/from the fs proc started to become not really maneagable. As a first step to fix this situation, join the fs and ui process.

remote open: open an url into telescope from outside of it if telescope is started with an url while there is already another instance of it running and the -S flag is not provided, the link will be automagically opened into the running instance of telescope. Telescope now listens on a UNIX domain socket in ~/.telescope/ctl (or ~/.cache/telescope/ctl if XDG is used) for commands.

move headers to include/