Add configuration option for indent spaces

[crtl]

I'm submitting a...

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

Current behavior

When generating any code all code is generated with 2 spaces for indents only.

Expected behavior

There should be a way to configure indent behaviour.

Minimal reproduction of the problem with instructions

nest g co test

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

Some people use 2 spaces some use 4.
Currently I have to reformat every file im generating.
This also was an issue with angular/cli for a long time untill they added the configuration.

Environment

[System Information]
OS Version     : Windows 10
NodeJS Version : v14.17.0
YARN Version    : 1.22.5

[Nest CLI]
Nest CLI Version : 7.6.0

[Nest Platform Information]
platform-express version : 7.6.15
common version           : 7.6.15
core version             : 7.6.15

[kamilmysliwiec]

We're tracking this here #316