migrate install_php.sh to support alpine apk/php:x.x-fpm-alpine specifics
migrate install_php.sh to support alpine apk/php:x.x-fpm-alpine specifics

Make use of docker-php-ext-(configure|install|enable) and add support for
special php extensions like

* xcache
* gd
* imagick

Use apk, but clean up the installation after building extensions is done.

claranet/spryker-base,claranet/spryker-base,claranet/spryker-base