[FEATURE] Create stacks without description

[cwe1ss]

Is your feature request related to a problem? Please describe.
When using terramate create, the resulting stack.tm.hcl always contains a description that equals the name, even if I set --description="".

We do not need the description field in many cases because the name and directory-path are self-explanatory.

Describe the solution you'd like
The description should either not be created at all (like all other optional fields) or there should be a way to omit it via a flag on terramate create.

Describe alternatives you've considered
The current workaround is to manually delete the description field and call terramate fmt afterwards (since the indentation needs to change)

[i4ki]

The stack.description is an optional stack field, then I think makes sense supporting not setting it if the user requests to do so. I think --description="" should work as intended or maybe making this flag negatable with --no-description.

@mariux wdyt?