Merge #1696

1696: disable php version expose r=Diman0 a=ronivay

## What type of PR?

enhancement

## What does this PR do?

Disable exposing PHP-version from webmails in x-powered-by header for security reasons.

## Prerequistes
Before we can consider review and merge, please make sure the following list is done and checked.
If an entry in not applicable, you can check it or remove it from the list.

- [N/A] In case of feature or enhancement: documentation updated accordingly
- [x ] Unless it's docs or a minor change: add [changelog](https://mailu.io/master/contributors/guide.html#changelog) entry file.


Co-authored-by: ronivay <roni@vayrynen.info>

towncrier/newsfragments/1696.misc

@@ -0,0 +1 @@
+Hide x-powered-by PHP-version header from webmails

webmails/rainloop/php.ini

@@ -1,3 +1,4 @@
+expose_php=Off
 date.timezone=UTC
 upload_max_filesize = {{ MAX_FILESIZE }}M
 post_max_size = {{ MAX_FILESIZE }}M

webmails/roundcube/php.ini

@@ -1,3 +1,4 @@
+expose_php=Off
 date.timezone=UTC
 upload_max_filesize = {{ MAX_FILESIZE }}M
 post_max_size = {{ MAX_FILESIZE }}M