moved key_derivation.rs from pbs_datastore to pbs-config/src/key_config.rs

Also moved pbs-datastore/src/crypt_config.rs to pbs-tools/src/crypt_config.rs.
We do not want to depend on pbs-api-types there, so I use [u8;32] instead of
Fingerprint.

src/backup/read_chunk.rs

@@ -4,7 +4,8 @@ use std::sync::Arc;
 
 use anyhow::{bail, Error};
 
-use pbs_datastore::crypt_config::{CryptConfig, CryptMode};
+use pbs_tools::crypt_config::CryptConfig;
+use pbs_api_types::CryptMode;
 use pbs_datastore::data_blob::DataBlob;
 use pbs_datastore::read_chunk::{ReadChunk, AsyncReadChunk};