Revert "Code refactoring. Improve folder structure. For better project implementation. Most hosting server have a default folder public or public_html insted of htdocs, htdocs is a exclusive folder for apache web server, for example is no the same folder in NGINX."

This reverts commit e91c2c6e.

Code refactoring. Improve folder structure. For better project implementation. Most hosting server have a default folder public or public_html insted of htdocs, htdocs is a exclusive folder for apache web server, for example is no the same folder in NGINX.

These files doesn't contain executable code and may pose a security
threat.

migration files.

New: Add module field to allow external modules to set their name when they add a new record during init/remove.