Feat sdiff inital with parser

[GunterSchmidt]

Add the sdiff utility in a basic version, see issue #16.

The PR replaces the PRs #159 and #188 as their content is merged in here.

Also a new parser is introduced, as I found too many issues when working with cmp.

feat: Introducing a new parser for all utils

This is a new fully working parser for the arg options.
The parser is written generically so it can be used in all diffutils tools.
The first implementation is done with sdiff. I already have a revised version for cmp as well.

I checked and discarded clap as tool, as the requirements are very individual and would require extensive tweaking of the clap functionality.

Features:

• Allows options to be abbreviated, e.g. --wi instead of --width
• Allows input like in GNU utils, e.g. the following are all identical
  • diff --ignore-case --minimal --width=50 file_a file_b
  • diff --ignore-case --minimal --width 50 file_a file_b
  • diff -i -d -w 50 file_a file_b
  • diff -id -w50 file_a file_b
  • diff -idw50 file_a file_b
• A number parser is available, which parses option arguments
  with optional byte units, e.g. =1024 or =1024KiB
• Default handling for --version and --help
• Returns the params or an Error Enum, which makes it library friendly.
• Contains error handling for the typical parsing errors:
  -- missing and extra operands
  -- invalid, ambiguous or conflicting options
  -- missing or not allowed option arguments
• Provides error text functions, e.g. add executable and 'Try --help' to message.