zpaq: add page

[dy-tea]

• 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):
  zpaq v7.15

[CLAassistant]

All committers have signed the CLA.

[tldr-bot]

The build for this PR failed with the following error(s):

pages/common/zpaq.md:4: TLDR016 Label for information link should be spelled exactly `More information: `

Please fix the error(s) and push again.