Add p0011: Container With Most Water

[MNnazrul]

Problem

• Number: 11
• Name: Container With Most Water
• Difficulty: Medium
• LeetCode Link: https://leetcode.com/problems/container-with-most-water/

Changes

• Solution file added in src/
• Module registered in src/lib.rs
• Tests included with LeetCode examples
• Tutorial added in book/src/problems/
• Entry added to book/src/SUMMARY.md
• Row added to problems table in README.md

CI Checks

• cargo fmt --check
• cargo clippy
• cargo test
• mdbook build