Make "outDir" for assets more configurable (depth level?)

I'm submitting a...

[ ] Regression 
[x] Bug report
[ ] Feature request
[ ] Documentation issue or request
[ ] Support request => Please do not submit support request here, instead post your question on Stack Overflow.

Current behavior

Asset are not being copied dist folder if they are included in a library folder (even when they are added to the nest-cli.json)

Expected behavior

assets should be always copied to dist if the file type / folder pattern is included in the nest-cli.json

Minimal reproduction of the problem with instructions

https://github.com/raydaim/NestTest

What is the motivation / use case for changing the behavior?

Cannot include assets with libraries such as fonts / css files ...

Environment

[System Information]
OS Version     : macOS Catalina
NodeJS Version : v10.16.3
YARN Version    : 1.21.1 

[Nest CLI]
Nest CLI Version : 7.1.2 

[Nest Platform Information]
platform-express version : 7.0.0
common version           : 7.0.0
core version             : 7.0.0

Start with the nest-cli.json asset configuration and the linked NestTest reproduction to trace how assets inside library folders are handled. Run the reproduction with the reported Nest CLI environment and verify that configured file types or folder patterns are copied into dist, including assets nested in libraries.