UTF-8 support in PHP images history

• 7ee6ff557e added UTF-8 localisation to the Arc image
• @Sandlayth fixed UTF-8 localisation in rDPHPFPM4d812fd6d

An incoherence

For web apps, it's out of the box handled by the base image, but for CLI apps, it's the app responsibility to implement it.

Plan is to standardize

To standardize the practice, we're moving UTF-8 support, using the rDPHPFPM4 code, directly in rDPHPCLI.