EZP-20920: Add EZP_INI_DIRECTORY_PERMISSION constant

[emodric]

This pull request fixes two issues I had with permissions in var folder:

• EZP_INI_FILE_PERMISSION was used to create the var/autoload directory as well as files inside of it. If we want our INI caches and autoload files to have, for example, 0660 permissions, it is not possible to enter the var/autoload directory by eZ Publish as no execute bit was set on it.
• eZINI class uses hardcoded 0777 value for creating var/cache/ini folder

With this pull request, both of those issues are resolved by using a new constant in config.php

[andrerom]

+1 but maybe add a JIRA enhancement issue for this.

[emodric]

@andrerom Issue created: EZP-20920 and title of the pull request updated.