Implement an analog of the templatefile terraform function

[kinseii]

What would you like to add
I want to use templating inside files, to substitute variable values, like the templatefile function in terraform does.

Why is this needed
This is necessary for templating the .yaml files of helm and k8s-manifest units.

This issue may have a connection to the issue at hand: #225

P.S.
Also, I don't understand what the apply_template option of the helm unit means? Can you clarify it here and add it to the documentation?

[kinseii]

It seems to be irrelevant, I figured out how to work with templates, it's similar to helm templates, obviously because of the development language go.

[romanprog]

It seems to be irrelevant, I figured out how to work with templates, it's similar to helm templates, obviously because of the development language go.

Also looks like a duplicate of ticket #225
It will be possible to read and apply the template to the files. The feature will be added in the next releases.