Always restrict valid template modifiers to an allow list

Always restrict valid template modifiers to an allow list

Previously this allow list was only used in enterprise mode, but it is
generally a useful security feature. Thus the allow list previously known as
`$enterpriseFunctions` is applied in call cases.

This also makes it easier for developers, as there will be less differences
between the enterprise mode and the non-enterprise mode.

As before this allow list can easily be extended if a useful function is
missing from it.