Prepare documentation for publication

[weierophinney]

This patch prepares the documentation for publication, with patches for the following:

• Converted from bookdown to mkdocs.
• Renamed files to remove zend.locator. prefix.
• Checked and corrected all headers. (Fixes Check All Headers In Documentation #3)
• Checked and corrected all code blocks. (Fixes Check Documentation Code Blocks #4)
• Checked and corrected all tables. (Fixes Check Documentation Tables #6)
• Checked and corrected all blockquotes. (Fixes Check For Blockquotes In Docs #7)
• Reviewed and edited for content and formatting. (Fixes Check Documentation For Other Things #5)
• Creation of documentation build automation.

Documentation is available now at https://zendframework.github.io/zend-loader/