Added move_to_front_encoding implementation

[Divakar-2508]

Description

This PR adds the Move-To-Front (MTF) Encoding algorithm under the compression category.

Algorithm Overview

Move-To-Front (MTF) Encoding is a lossless data compression algorithm that replaces each character with its position in a dynamically updated list. Every time a character is accessed, it moves to the front of the list. This technique is commonly used as a preprocessing step before further entropy encoding, such as Burrows-Wheeler Transform (BWT).

For more details: [Move-To-Front Transform - Wikipedia](https://en.wikipedia.org/wiki/Move-to-front_transform)

Implementation Details

• Uses a Vec as a lookup queue for efficient front insertions.
• Implements both encoding and decoding functions.
• Includes unit tests to verify correctness.

Type of Change

• New feature (non-breaking change which adds functionality)

Checklist

• I ran the following commands using the latest version of rust nightly.
• I ran cargo clippy --all -- -D warnings just before my last commit and fixed any issue that was found.
• I ran cargo fmt just before my last commit.
• I ran cargo test just before my last commit and all tests passed.
• I added my algorithm to the corresponding mod.rs file within its own folder, and in any parent folder(s).
• I added my algorithm to DIRECTORY.md with the correct link.
• I checked CONTRIBUTING.md, and my code follows its guidelines.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.50%. Comparing base (b4aecf4) to head (d3cd07e).

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #874   +/-   ##
=======================================
  Coverage   95.49%   95.50%           
=======================================
  Files         316      317    +1     
  Lines       22919    22948   +29     
=======================================
+ Hits        21887    21916   +29     
  Misses       1032     1032           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.