[typescript-nestjs] allow configuration with forRootAsync

[BerniWittmann]

Allow the configuration of the nestjs module with different providers via forRootAsync. This will RESOLVE #15269.

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[BerniWittmann]

@TiFu @taxpon @sebastianhaas @kenisteward @Vrolijkx @macjohnny @topce @akehir @petejohansonxo @amakhrov @davidgamero @mkusaka
I'd be glad about your review on my PR to add more configuration options to typescript-nestjs generator. This will resolve #15269

[macjohnny]

LGTM, thanks for your contribution!