Vector style service

[okauppinen]

• create table for vector styles
• add instance default vector style
• migrate styles from wfs, vectortile and tiles3d options to new table
• add service, service impl and mapper

Migrate style consistency:
https://github.com/oskariorg/oskari-frontend/blob/master/bundles/mapping/mapmodule/domain/VectorStyle.js#L49-L84

Instance default style (wrapped inside featureStyle) from:
https://github.com/oskariorg/oskari-server/blob/master/service-base/src/main/java/fi/nls/oskari/domain/map/wfs/WFSLayerOptions.java#L137-L172

style column content:

• oskari: {featureStyle: {}, optionalStyles: []}
• external: { ..external style definitions.. }

UPDATED:

• layer -> layer_id and column type nullable integer (instance default style)
• creator nullable (admin styles)
• foreign key constraint for creator and layer_id -> on delete cascade