Loading Goal reports calls the API with segmentation which can be slow and should be pre-processed

[mattab]

Currently, loading a Goal report causes an API call with &segment=visitorType==returning,visitorType==returningCustomer

See code:
https://github.com/piwik/piwik/blob/master/plugins/VisitFrequency/API.php#L25

This is fine, but we should ensure that this specific API call with this specific segment is pre-processed as part of the archive.php call.

[mattab]

See #3144 as a requirement to fix

[mattab]

Very important to fix as this is the only piece of data not pre-archived in Piwik.

[mattab]

In 50e2aad: Fixes #2981 Calling API.get in CronArchive. This will result in VisitFrequency.get being called therefore pre-processed as well.

[mattab]

In 11b8ef2: URL encoding the segment for consistency refs ##2981

[mattab]

In 1fd459b: Refs #2981 Fix display of visits in archive.php output

[mattab]

See follow up #5132 Goals & archiving settings