feat: add ability to update NGINX IC, Helm, and Elastic related variables at startup

[qdzlug]

Is your feature request related to a problem? Please describe. Although we provide the ability to update the configuration for deployment outside of the startup script, it is somewhat difficult for first-time users to understand the relationship, syntax, etc.

The three areas that are most commonly updated are:

• The details (version, type, location) of the NGINX IC deployment.
• The helm timeout value.
• The number of replicas for each Elastic service.

Describe the solution you'd like Build in logic within the startup script to allow the user to specify this information.

Describe alternatives you've considered n/a

Additional context n/a