[feature](paimon) Add Paimon C++ Reader Support for Doris

[suxiaogang223]

What problem does this PR solve?

Overview

This PR adds Paimon C++ reader support to Doris, enabling reading Paimon table data through C++ interfaces. The implementation includes PaimonCppReader, Paimon Doris file system implementation, and related configuration and integration work.

Major Changes

1. Third-party Library Integration

• Added paimon-cpp download and build support in thirdparty/build-thirdparty.sh
• Updated be/cmake/thirdparty.cmake and be/CMakeLists.txt to support compilation and linking of paimon-cpp library

2. PaimonCppReader Implementation

• Added new files be/src/vec/exec/format/table/paimon_cpp_reader.h and .cpp
• Implemented PaimonCppReader class for reading Paimon table data
• Integrated with FileScanner to support reading Paimon data through file scanner

3. Paimon Doris File System Implementation

• Added new files be/src/vec/exec/format/table/paimon_doris_file_system.h and .cpp
• Implemented PaimonDorisFileSystem class, providing an adapter layer between Paimon and Doris file systems
• Implemented file system registration mechanism

Check List (For Author)

• Test

  • Regression test
  • Unit Test
  • Manual test (add detailed scripts or steps below)
  • No need to test or manual test. Explain why:
    • This is a refactor/code format and no logic has been changed.
    • Previous test can cover this change.
    • No code files have been changed.
    • Other reason

• Behavior changed:

  • No.
  • Yes.

• Does this need documentation?

  • No.
  • Yes.

Check List (For Reviewer who merge this PR)

• Confirm the release note
• Confirm test cases
• Confirm document
• Add branch pick label

[hello-stephen]

Thank you for your contribution to Apache Doris.
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