chcat: add page

[pranlawate]

Adds documentation for the chcat command.

Contributes to #11896

• The page(s) are in the correct platform directories: common, linux, osx, windows, sunos, android, etc.
• The page(s) have at most 8 examples.
• The page description(s) have links to documentation or a homepage.
• The page(s) follow the content guidelines.
• The page(s) follow the style guide.
• The PR title conforms to the recommended templates.
• Version of the command being documented (if known): policycoreutils-python-utils-3.7-8.fc41.noarch