LPS-47328 remove usages of LiferayBase

Hi @sergiogonzalez,

For LPS-47325 I'm trying to unify local and non local repositories by creating a common parent class. I cannot do that cleanly because of the `LiferayBase` class: it is used as a superclass for local repositories and other non related classes (`FileEntryUtil`, `FolderUtil` and `RepositoryModel`). As this doesn't make much sense and makes things artificially difficult, I believe we should get rid of it.

Given that all that `LiferayBase` contains are util methods, I've moved them to a proper util class and removed all references to `LiferayBase`.