New Bookmark Command

[azaleacolburn]

Description

Adds a new subcommand called bookmark as per #1014

Usage

zoxide bookmark foo ~/bar creates a bookmark in the database called foo which aliases to bar.

Then, zoxide query foo automatically outputs ~/bar before even opening a Stream. However, it doesn't match, so zoxide query fooo ignores the bookmarking system and matches dirs on fooo.

This PR restructures the database, by turning dirs into a tuple containing the old dirs (a vector of directories) and a bookmarks hashmap. They must be under the same field so they can be serialized and deserialized together, while obeying the self_referencing struct system.

Warning

Because of this restructuring, old databases will no longer be deserializable.

However, this PR also adds additional code to the deserialize command, which will fall back on deserializing just the vector of Dirs, then reserializing the database with those dirs and an empty hashmap.
So existing zoxide instances should still operate perfectly, but old databases will be changed.

[lengyijun]

I don't like bookmark system.
Bookmark should be done in other tools rather than zoxide.

[azaleacolburn]

I don't like bookmark system. Bookmark should be done in other tools rather than zoxide.

Discussions about the viability of bookmarking as a feature can be had in #1014.