DRILL-8552: Add Storage Plugin for Apache Accumulo

[cgivre]

DRILL-8552: Add Storage Plugin for Apache Accumulo

Description

This PR introduces a new storage plugin for Apache Accumulo, enabling Drill to query Accumulo tables using standard SQL.

Features:

• Full SQL query support for Accumulo tables
• Dynamic schema discovery (column families as MAPs)
• Filter pushdown (row key ranges to Accumulo Range scans)
• Projection pushdown (column family/qualifier selection)
• Limit pushdown (early scan termination)
• Sort pushdown (ORDER BY row_key uses natural ordering)

Authentication modes:

• PASSWORD: Username/password authentication
• KERBEROS + SHARED_USER: Service principal for all queries
• KERBEROS + USER_IMPERSONATION: Delegation tokens for per-user identity
• USER_TRANSLATION: Per-user Accumulo credentials from CredentialsProvider

Key components:

• AccumuloStoragePlugin/Config: Plugin configuration and lifecycle
• AccumuloConnectionManager: Centralized auth and client management
• AccumuloGroupScan/SubScan: Distributed scan planning
• AccumuloRecordReader: Data reading and vector population
• AccumuloPushFilterIntoScan: Filter pushdown optimizer rule
• AccumuloPushSortIntoScan: Sort pushdown optimizer rule
• DelegationTokenInfo: Serializable token wrapper for distributed execution

Documentation

See README.md

Testing

Added extensive unit tests.

[cgivre]

@shfshihuafeng Thanks for your review. I believe I addressed all your review comments. Would you please take a look?
@cgivre hi, I took another look and found that the AccumuloClient resource leak I mentioned earlier is still not fixed. do you think this scenario is not an issue that needs to be addressed?

AccumuloClient client = null;
try {
  client = ...;
  // build reader
} catch (Exception e) {
  throw ...;
} finally {
  if (client != null) {
    client.close();
  }
}

[shfshihuafeng]

LGTM +1