Add redb adapter

[Dimchikkk]

https://github.com/cberner/redb

Add redb adapter and set it as default.

Fixes: #32

[johanhelsing]

Oooh, nice!! Looks like just like we want, any drawbacks at all compared to sled?

Implementation looks solid.

[Dimchikkk]

Oooh, nice!! Looks like just like we want, any drawbacks at all compared to sled?

Implementation looks solid.

I don't have much knowledge about sled or redb. However, sled doesn't work properly on my M1 laptop when it comes to cleaning data. On the other hand, redb has been functioning as expected so far. A notable advantage of redb is that it stores all the data in a single file, unlike sled which uses multiple files. I consider this an advantage because it facilitates easy sharing of the entire database. If you're interested in the design of redb, you can refer to their documentation at: https://github.com/cberner/redb/blob/master/docs/design.md. It's implemented in pure Rust and doesn't load the entire database into memory. The project appears to be in good health and recently reached version 1.0.0.