Modularize & Refactor

Remove check redundant for iThemes secuity
Rename folder plublic --> modules
Remove view for public
Add blank index files
Refactor Sunny_Settings & Sunny_Sanitization_Helper: Dependency inversion principle
Re-structure files: admin/mailer --> mailer
Re-structure files: public --> modules

Rename folder plublic --> modules & remove view for public

Add blank index files

Refactor Sunny_Settings & Sunny_Sanitization_Helper: Dependency inversion principle

Re-structure files: admin/mailer --> mailer & public --> modules
Refactor redundant code