Add cron as a global service

[sagarnasit]

closes: EasyEngine/easyengine#1365

Depends on:
https://github.com/EasyEngine/easyengine/pull/1368/files
EasyEngine/cron-command#44

[mrrobot47]

Use function: EE_DOCKER::get_mounting_volume_array() as in all of above to generate volumes. As the volume generation differs in Linux and macOS.

For the volume /var/run/docker.sock - You can use skip_volume:

service-command/src/helper/service-utils.php

Lines 155 to 160 in 0013571

	[
	'name' => '/var/run/docker.sock',
	'path_to_symlink' => '/var/run/docker.sock',
	'container_path' => '/tmp/docker.sock:ro',
	'skip_volume' => true,
	],

Once, this change is done, for Linux systems, the cron directory inside the EE_SERVICE_DIR will be a docker volume. So, you'll have to write migrations to take backup of the previous cron directory and then once volume directory get's symlinked, need to restore that data.