Add branch merge strategies

[ForeverAngry]

Feature Request / Improvement

Add merge strategies commonly used in version control systems to pyiceberg. Motivated by some of the discussion found here https://github.com/apache/iceberg-python/issues/2428:

1. MERGE: creating a merge commit that preserves history of both branches
2. SQUASH: condenses all commits from source branch into a single clean commit on target branch
3. REBASE: creates linear history by replaying commits from source branch on top of target branch
4. CHERRY_PICK: selects and applies specific individual commits from one branch to another
5. FAST_FORWARD: moves target branch pointer forward when no divergent commits exist (no merge commit needed)

[Ferdinanddb]

I would really be interested by this feature!