feat: add context to disable some features cluster deploy

[blacha]

Motivation

I am deploying a few testing EKS clusters and I need a way to disable some features as I dont need them for the testing clusters,

I would also like to make it easier for myself to deploy clusters with custom names to allow multiple clusters to be running in the same AWS account

Modifications

adds context variables

Add a Suffix to the cluster name and scratch bucket name

-c cluster-suffix=blacha

Disable features

Turn off RDS and slack notifications

-c no-database=true
-c no-slack=true

I have also made mantainer-arns optional as they are not required to have a working cluster.

Verification

Deployed into nonprod