Allow setting php.ini and php-fpm pool setting via individual env vars

[baschny]

The PHPINI__... and PHPFPM__... allow to set individual settings for php.ini and php-fpm.conf (pool settings) using individual environment variables. Just replace the . in the settings by __. Examples:

Upper case allowed (will be lower-cased):

PHPINI__SESSION__SAVE_HANDLER=redis
PHPINI__SESSION__SAVE_PATH='"tcp://redis:6379?persistent=1&weight=1&database=10&prefix=PHPSESSID:"'
PHPINI__REDIS__SESSION__LOCKING_ENABLED=1

Or:

PHPFPM__request_terminate_timeout=30s
PHPFPM__pm__max_children=15

Note: make sure the double quotes " are part of the "string" that ends up in the ENV variable, so quote as necessary, because this string is copied "as is" to the ini files). See example above for the PHPINI__SESSION__SAVE_PATH - this is the syntax for a .env file.

[baschny]

@remuslazar ich merge das mal, dann kannst du das einfach mal nutzen und ausprobieren im anderen PR, ok? Bin zufrieden damit, falls was nicht in Ordnung ist, kann man das dann noch in einem fup lösen.