Improve bash completion with alias extraction and submodule support

[tomers]

Enhanced the bash completion script with the following improvements:

• Extract both recipes and aliases from 'just --list' output instead of only using 'just --summary', providing more complete completions
• Add support for submodule recipe completion when typing 'just '
• Automatically detect module justfiles in common locations (, /justfile, modules/, modules//justfile)
• Parse aliases from both [alias: ...] and [aliases: ...] patterns in list output
• Add fallback to --summary if --list fails for better compatibility
• Improve recipe name extraction to handle edge cases better

These changes make tab completion more comprehensive and useful for projects using just modules and aliases.