Improved command for pulling PHP Errors from a Pressable site

[ahegyes]

Implements a new command for retrieving the PHP error logs of a Pressable site by leveraging the Atomic API when the default log location is used, and the legacy file parsing method when not.

For example, sites that have WP_DEBUG turned on will log all their errors in /srv/htdocs/wp-content/debug.log whereas the default location is /tmp/php-errors. The API only looks in the default location so we would miss out on all the PHP Fatal Error entries that occur after WP modified the error log location.

The newly introduced --source option allows forcing retrieval either via api or from file if the default auto mode is not returning the expected results.

Use like this:

team51 pressable:list-site-php-errors <site_id_or_url>
team51 pressable:list-site-php-errors <site_id_or_url> --limit 25 --severity "Fatal error"
team51 pressable:list-site-php-errors <site_id_or_url> --source file

Fixes #173 and #184

[ahegyes]

Hi @tiagonoronha and @tommusrhodus! I pinged you about this because you were passionate about using the Pressable API to retrieve the error logs. This PR accomplishes exactly that with the added advantage of working also on sites that have WP_DEBUG turned on (or other means of changing the error log location).

Ping me on Slack if you want examples of our sites that do that -- I didn't want to note them here publicly 😄