Allow to create case insensitive indexes via annotations

[jakubpradzynski]

Hi,

the option for creating case insensitive index in MongoDB is available by setting collation. Specifically locale and strength values. It's described in MongoDB documentation.

Currently, annotations @Indexed and @CompoundIndex don't have collation in parameters to set.
Such option is available for @Document annotation but this will set value for all indexes in collection.

[christophstrobl]

Thank you for the PR @jakubpradzynski !

[StefanTirea]

Hi, actually I created the PR and referenced this ticket because it would also solve this one 😁. I would be happy for feedback on it if you find the time to review it @christophstrobl .

[chandni-navani]

Can someone explain how to use this new index and what versions it's available in?