Introducing Damus Notedeck: a nostr browser

This splits notedeck into:

- notedeck
- notedeck_chrome
- notedeck_columns

The `notedeck` crate is the library that `notedeck_chrome` and
`notedeck_columns`, use. It contains common functionality related to
notedeck apps such as the NoteCache, ImageCache, etc.

The `notedeck_chrome` crate is the binary and ui chrome. It is
responsible for managing themes, user accounts, signing, data paths,
nostrdb, image caches etc. It will eventually have its own ui which has
yet to be determined.  For now it just manages the browser data, which
is passed to apps via a new struct called `AppContext`.

`notedeck_columns` is our columns app, with less responsibility now that
more things are handled by `notedeck_chrome`

There is still much work left to do before this is a proper browser:

- process isolation
- sandboxing
- etc

This is the beginning of a new era! We're just getting started.

Signed-off-by: William Casarin <jb55@jb55.com>

crates/notedeck_columns/src/lib.rs

@@ -7,7 +7,6 @@ mod abbrev;
 pub mod accounts;
 mod actionbar;
 pub mod app_creation;
-mod app_size_handler;
 mod app_style;
 mod args;
 mod colors;
@@ -15,35 +14,24 @@ mod column;
 mod deck_state;
 mod decks;
 mod draft;
-mod filter;
-mod fonts;
 mod frame_history;
 mod images;
-mod imgcache;
 mod key_parsing;
 pub mod login_manager;
 mod multi_subscriber;
-mod muted;
 mod nav;
-mod note;
-mod notecache;
 mod notes_holder;
 mod post;
 mod profile;
 pub mod relay_pool_manager;
-mod result;
 mod route;
 mod subscriptions;
 mod support;
 mod test_data;
-mod theme_handler;
 mod thread;
-mod time;
-mod timecache;
 mod timeline;
 pub mod ui;
 mod unknowns;
-mod user_account;
 mod view_state;
 
 #[cfg(test)]