Fix Derby compatibility in metadata DAOs

[xiaotongsaying]

Remove MySQL-specific identifier quoting from metadata DAO queries. Use JDBC generated keys instead of LAST_INSERT_ID(). Add the default Derby JDBC driver configuration.
Update fresh installations to use PIXELS_HOME for Derby and var paths. Adjust the affected DAO test for generated-key retrieval.

What does this PR do?

This PR improves Derby compatibility in the metadata DAO implementation while
preserving MySQL support.

Changes

• Remove MySQL-specific backtick quoting from metadata DAO SQL statements.
• Replace SELECT LAST_INSERT_ID() with JDBC RETURN_GENERATED_KEYS.
• Use SQL expressions supported by both Derby and MySQL.
• Add the Derby JDBC driver to the default metadata configuration.
• Configure fresh installations to place the Derby database and runtime
  directories under PIXELS_HOME.
• Update the affected DAO test to mock JDBC generated-key retrieval.

Why is this needed?

The default metadata database is Derby, but some DAO statements still use
MySQL-specific SQL syntax. These statements can fail when metadata operations
are executed against Derby.

Testing

Tested on:

• Huawei Cloud Kunpeng ARM64
• Kylin Linux Advanced Server V10 SP3
• Maven 3.9.16
• Pixels CLI and coordinator using JDK 8
• Apache Derby embedded metadata database
• Trino 466 using ARM64 JDK 23

Verified the following flow:

1. Built and installed Pixels from the modified source.
2. Initialized a fresh Derby metadata database with INIT-META.
3. Started etcd and the Pixels coordinator.
4. Created the TPC-H region table through the Pixels Trino connector.
5. Loaded the TPC-H region.tbl file with pixels-cli.
6. Confirmed that a Pixels .pxl file was generated.
7. Queried the table through Trino.

Query:

SELECT count(*), sum(r_regionkey) FROM tpch.region;

Related to #1393
Related to #1394