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.

tests/blob_writer.rs

@@ -4,7 +4,8 @@ use std::io::Cursor;
 use std::io::{Read, Write, Seek, SeekFrom };
 use lazy_static::lazy_static;
 
-use pbs_datastore::{CryptConfig, DataBlob, DataBlobReader, DataBlobWriter};
+use pbs_tools::crypt_config::CryptConfig;
+use pbs_datastore::{DataBlob, DataBlobReader, DataBlobWriter};
 
 lazy_static! {
     static ref TEST_DATA: Vec<u8> = {