Add support for BITPOS command

[soumya-codes]

BITPOS Command Implementation

Overview

This PR implements the Redis-compatible BITPOS command. BITPOS returns the position of the first bit set to 1 or 0 in a string within a given range.

Features

• Implemented BITPOS command following Redis specifications.
• Supports for optional start and end parameters
• Includes handling for both bit and byte range types

Next Steps

• Consider adding benchmarks.
• Ensure consistent handling of encoded types for the values for all Dice DB commands.

Updates #143