Clean up hash functions for FIPS compliant build

md5 is blocked for “FIPS compliant” libraries, SHA-1 and SHA-256 will be soon to be deprecated. We should avoid these hash algorithms in Impala code.

IMPALA-10205, IMPALA-10206, IMPALA-10207 , IMPALA-10298,  IMPALA-10305  track the FIPS blocking issues for the upcoming release (7.1.5). This Jira tracks the remaining non-block issues for cleanup in the future.
 

• Key Agreement and Authentication Algorithms in be/src/kudu/security
  Kudu security code support SHA-256 for message digest and signing key
  GetServerEndPointChannelBindings() in be/src/kudu/security/cert.cc
  DigestType in be/src/kudu/security/crypto.h and crypto.cc
  TokenSigningPrivateKey::Sign()and TokenSigningPublicKey::VerifySignature() in be/src/kudu/security/token_signing_key.cc  
   
• Integrity and Authentication Hash
  Openssl utility function generate integrity and authentication hash in SHA-256
  IntegrityHash() and AuthenticationHash() in be/src/util/openssl-util.h
   
• RPC generate cookie
  RPC generate cookie in SHA-256:
  GenerateCookie() in be/src/rpc/authentication-util.cc
   
• Python script for dev/test environment
  In Python script infra.deploy/deploy.py, it calls hashlib.md5() to generate hash for hostId when generating role_name for service as below:
     md5 = hashlib.md5()
     md5.update(master_host.hostId)
     new_role_name = "%s-%s-%s" % (new_name, rcg.roleType, md5.hexdigest())
  We use md5 for non-security purposes and there is no dependency on the hash value so we can change the hash algorithm. Except the md5 hash algorithm, hashlib supports SHA1/SHA224/SHA256/SHA384/SHA512 (https://docs.python.org/2/library/hashlib.html). We can change md5 to sha512.
   
  - PostgreSQL configuration for dev/test environment
  In Shell script bin/bootstrap_system.sh, it set the password authentication methods of PostgreSQL as md5 to accept md5-hashed passwords from localhost. 
  According to PostgreSQL document https://www.postgresql.org/docs/11/auth-password.html, it recommends to upgrade md5 to scram-sha-256, but we have to ensure that the client libraries are new enough to support SCRAM.