This PR adds types to the `crdt` directory to make the structure of the
merkle tree (really a merkle radix trie) clearer.

---------

Co-authored-by: Jed Fox <git@jedfox.com>
Co-authored-by: Matiss Janis Aboltins <matiss@mja.lv>

I've updated the return values in `sync/index` to sensible values based
on how they're being called.

I've updated the type of `msg.value` to be `string | number | null` to
match the values expected by `serializeValue`

Another batch of `loot-core` migrated.

Upgraded `fast-check` to improve unit test performance.

*  (prettier) adding trailing commas

* More commas

*   upgrade eslint-plugin-import and fix issues

* Change import ordering

* style: enforce sorting of imports

* style: alphabetize imports

* style: merge duplicated imports

* style: enforce ordering of imports

* style: sort imports in loot-core

* style: sort imports in desktop-client

* style: sort imports in loot-design

* style: manual fixes