Import Lombok and override the equals and hashCode methods for expression and plan nodes

[LantaoJin]

Description

Some expression and plan nodes in PPL Spark lack of equals and hashCode methods which may cause potential bugs.
Import Lombok dependency for ppl-spark-integration module and align the related codes with SQL's implementation.

This is a code refactor PR which doesn't introduce any new functionality.

Issues Resolved

Resolves #702

Check List

• [ ] Updated documentation (ppl-spark-integration/README.md)
• [ ] Implemented unit tests
• [ ] Implemented tests for combination with other commands
• Commits are signed per the DCO using --signoff

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[LantaoJin]

@YANG-DB this is a refactor PR. Please review and merge it ASAP if possible. Since it includes a lot of file changes that easy to be conflicted with other PRs.

[opensearch-trigger-bot]

The backport to 0.5-nexus failed:

The process '/usr/bin/git' failed with exit code 128

To backport manually, run these commands in your terminal:

# Navigate to the root of your repository
cd $(git rev-parse --show-toplevel)
# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add ../.worktrees/opensearch-spark/backport-0.5-nexus 0.5-nexus
# Navigate to the new working tree
pushd ../.worktrees/opensearch-spark/backport-0.5-nexus
# Create a new branch
git switch --create backport/backport-703-to-0.5-nexus
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 38ca314034021c34765713c016bcf3cef775efab
# Push it to GitHub
git push --set-upstream origin backport/backport-703-to-0.5-nexus
# Go back to the original working tree
popd
# Delete the working tree
git worktree remove ../.worktrees/opensearch-spark/backport-0.5-nexus

Then, create a pull request where the base branch is 0.5-nexus and the compare/head branch is backport/backport-703-to-0.5-nexus.

[opensearch-trigger-bot]

The backport to 0.5 failed:

The process '/usr/bin/git' failed with exit code 128

To backport manually, run these commands in your terminal:

# Navigate to the root of your repository
cd $(git rev-parse --show-toplevel)
# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add ../.worktrees/opensearch-spark/backport-0.5 0.5
# Navigate to the new working tree
pushd ../.worktrees/opensearch-spark/backport-0.5
# Create a new branch
git switch --create backport/backport-703-to-0.5
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 38ca314034021c34765713c016bcf3cef775efab
# Push it to GitHub
git push --set-upstream origin backport/backport-703-to-0.5
# Go back to the original working tree
popd
# Delete the working tree
git worktree remove ../.worktrees/opensearch-spark/backport-0.5

Then, create a pull request where the base branch is 0.5 and the compare/head branch is backport/backport-703-to-0.5.

[LantaoJin]

@YANG-DB This is a refactor PR and no either new expression node or plan node introduced to branch 0.5 based on this code change, it could be not required in both 0.5 and 0.5-nexus. How about just leave it in 0.6 only to save time.