Implement new exercise: Alphametics

[rabestro]

This issue is to track the implementation of the "Alphametics" exercise for the AWK track. The core task is to solve puzzles of the format WORD1 + WORD2 = WORD3.

The primary focus for implementation should be adhering to the following input and output specifications, as discussed:

Input Format

• The script will receive the alphametic puzzle as a single string via standard input (stdin).
• The puzzle string will follow the format WORD1 + WORD2 = WORD3.
  • Example stdin: SEND + MORE = MONEY

Output Format

• The script must produce a single line of output for a valid solution.
• This line should consist of space-separated LETTER=DIGIT pairs.
• The pairs must be sorted alphabetically by the letter.
• If the puzzle has multiple solutions, outputting any one valid solution that adheres to this format is acceptable.
  • Example output for SEND + MORE = MONEY:

    D=7 E=5 M=1 N=6 O=0 R=8 S=9 Y=2