[ISSUE #218]📌Implement DefaultMappedFile initialization

[mxsm]

Which Issue(s) This PR Fixes(Closes)

Fixes #218

Brief Description

How Did You Test This Change?

[codecov]

Codecov Report

Attention: Patch coverage is 18.56287% with 136 lines in your changes are missing coverage. Please review.

Project coverage is 13.03%. Comparing base (32fe9c9) to head (3b9b181).

Files	Patch %	Lines
...tmq-store/src/log_file/mapped_file/default_impl.rs	19.56%	111 Missing ⚠️
rocketmq-store/src/base/put_message_context.rs	0.00%	25 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #219      +/-   ##
==========================================
+ Coverage   12.98%   13.03%   +0.05%     
==========================================
  Files         136      137       +1     
  Lines        6831     6996     +165     
==========================================
+ Hits          887      912      +25     
- Misses       5944     6084     +140     

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