refactor(storage): use common file handler

[dan-starkware]

Pull Request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no API changes)
• Build-related changes
• Documentation content changes
• Other (please describe):

What is the current behavior?

Issue Number: N/A

What is the new behavior?

Does this introduce a breaking change?

• Yes
• No

Other information

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This change is 

[codecov]

Codecov Report

Merging #1281 (669a97a) into main (ff1500d) will increase coverage by 0.02%.
The diff coverage is 77.08%.

@@            Coverage Diff             @@
##             main    #1281      +/-   ##
==========================================
+ Coverage   72.96%   72.99%   +0.02%     
==========================================
  Files          84       84              
  Lines        7968     7972       +4     
  Branches     7968     7972       +4     
==========================================
+ Hits         5814     5819       +5     
- Misses       1228     1229       +1     
+ Partials      926      924       -2     

Files	Coverage Δ
crates/papyrus_storage/src/mmap_file/mod.rs	67.03% <77.08%> (+2.66%)	⬆️

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[yair-starkware]

Reviewed 1 of 1 files at r1, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @dan-starkware)

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crates/papyrus_storage/src/mmap_file/mod.rs line 102 at r1 (raw file):

/// A wrapper around `MMapFile` that provides both write and read interfaces.
#[derive(Clone, Debug)]
pub struct FileHandler<V: StorageSerde> {

I think this struct should be private (and move down in the file, maybe even into a module)

Code quote:

pub 

[dan-starkware]

Reviewable status: 0 of 1 files reviewed, 1 unresolved discussion (waiting on @yair-starkware)

---

crates/papyrus_storage/src/mmap_file/mod.rs line 102 at r1 (raw file):

Previously, yair-starkware (Yair) wrote…

I think this struct should be private (and move down in the file, maybe even into a module)

Done.

[yair-starkware]

Reviewed 1 of 1 files at r3, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @dan-starkware)

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crates/papyrus_storage/src/mmap_file/mod.rs line 143 at r3 (raw file):

/// Represents a memory mapped append only file.
#[derive(Debug)]
pub struct MMapFile<V: StorageSerde> {

Private too?

Code quote:

pub

[dan-starkware]

Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @yair-starkware)

---

crates/papyrus_storage/src/mmap_file/mod.rs line 143 at r3 (raw file):

Previously, yair-starkware (Yair) wrote…

Private too?

Sure in the next PR