Provide PHP third party library version details

As with #2826110: Provide Javascript library version details, I think for the initial release of this, we can add some config to the warden config variables which defines that third party PHP libraries and version number which can then be read by Warden Server.

We can look at the options of automating the list of PHP library versions at a later date.

In the update for #2826110: Provide Javascript library version details there is a 'js_library' array key which contains this information. We should look at changing this to just be a 'libraries' key, which will then contain a 'js' subkey for the Javascript library version information and a 'php' subkey for the PHP library version information.

Something like:

'libraries' => [
  'js' => [
    'foo' => 1.1,
    'bar' => 5.4,
  ],
  'php' => [
    'fuzz' => 3.2,
    'bazz' => 1.11.8
  ],
];

Here is the patch for this change.

This has been committed to the 8.x-1.x branch now so we can get the 7.x branch patch

Here is the patch for 7.x-1. branch

This has now been updated for both 7.x and 8.x branches