Remove redundant types and add specific array-types

[gauthierm]

Description

Removes @property docblocks in favour of @var docs. Adds specific array types for local cache arrays.

See previous #120

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1. Make sure Jenkins CI passes
2. Make sure type inference in IDE still works.

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[cviebrock]

The @var where the property is defined should be made nullable too, I'd think.

[gauthierm]

The column in the DB is non-nullable.