Adding Builder pattern in MMapDirectory.java

### Description

[MMapDirectory.java](https://github.com/apache/lucene/blob/main/lucene/core/src/java/org/apache/lucene/store/MMapDirectory.java) has 4 constructors and setters like `setPreload()` and `setReadAdvice()`. I see two issues here:

- Adding new arguments require permutation of constructors arguments and could lead to more growth in number of constructors.
- Since these setters can be called anytime after creation of a MMapDirectory instance, I am not sure if they are safe. Because configuration is mutable via setters, a change made by one thread (e.g., toggling preload) can lead to inconsistent behavior in other threads?

I think Builder pattern could be better suited here, it would eliminate need of multiple constructors and would make the MMapDirectory instance immutable. I am happy to contribute a PR but would love to hear thoughts on it as it will be a big API change.

Start with lucene/core/src/java/org/apache/lucene/store/MMapDirectory.java, reviewing its four constructors and the setPreload() and setReadAdvice() setters. The issue does not define an accepted API or implementation scope; completion would require maintainer agreement on the proposed design before a PR can be evaluated.

Written by the indexing model from the issue text.