BP-25: MovingChecksumToProto--Refactor the checksum part of bookkeeper

Descriptions of the changes in this PR:

Current the checksum implementation is in client module while the checksum semantic is more close to protocol. Moreover, moving the checksum implementation to protocol will avoid server module's dependency to client module when doing checksum in server side.

Master Issue: #1007

Author: Arvin <arvindevel@gmail.com>

Reviewers: Enrico Olivelli <eolivelli@gmail.com>, Sijie Guo <sijie@apache.org>, Venkateswararao Jujjuri <vjujjuri@salesforce.com>

This closes #1008 from ArvinDevel/BP_25_MovingChecksumToProto

site/bps/BP-25-MovingChecksumToProto.md

@@ -0,0 +1,27 @@
+---
+title: "BP-25: MovingChecksumToProto--Refactor the checksum part of bookkeeper"
+issue: https://github.com/apache/bookkeeper/issues/1007
+state: "Accepted"
+release: "N/A"
+---
+
+### Motivation
+
+Current the checksum implementation is in client module while the checksum semantic is more close to protocol. Moreover, moving the checksum implementation to protocol will avoid server module's dependency to client module when doing checksum in server side.
+
+### Public Interfaces
+
+An internal refactor not affecting public interfaces.
+
+### Proposed Changes
+
+Move the DigestManager and related classes to proto module
+
+### Compatibility, Deprecation, and Migration Plan
+N/A
+
+### Test Plan
+The original all tests should work as before.
+
+### Rejected Alternatives
+N/A

site/community/bookkeeper_proposals.md

@@ -85,7 +85,7 @@ using Google Doc.
 
 This section lists all the _bookkeeper proposals_ made to BookKeeper.
 
-*Next Proposal Number: 23*
+*Next Proposal Number: 26*
 
 ### Inprogress