Rework vernacular name handeling

[SanderDevisscher]

@mvarewyck this requires some changes into how searching by vernacular names are used in the app, namely:

• The vernacular name filter should happen based on vernacular_name_nl_list, vernacular_name_fr_list | vernacular_name_en_list
• The vernacular name displayed in the table should be vernacular_name_nl, vernacular_name_fr | vernacular_name_en

Originally posted by @SanderDevisscher in #393