Split shortcut registry from components

[mattrunyon]

ShortcutRegistry is currently in the @deephaven/components package and is the only item that is a singleton. Since it's a singleton, it requires @deephaven/components to be a peer dependency so only 1 version of it exists within a repo.

Split out the shortcut registry and change @deephaven/components to a regular dependency within our packages. Add @deephaven/shortcuts as a peer dependency. Alternatively, provide some way for plugins/modules to add shortcuts and combine the shortcut definitions into the @deephaven/shortcuts package instead of having each package create the shortcuts it uses (might not be the best choice though)