support xts yaml file creation and modifcation support

[TB-1993]

Goal: Upgrade the XTS core tool to support creation and modification of .xts yaml files

Currently, users have to create their .xts yaml files manually before xts can be used. This upgrade would add a CLI interface users could use to make changes to their yaml files and create new yaml files, with sections specified by the users. This interface would allow users to add new sections or new entries to existing sections, by asking them for the required information. This would allow for users to do the yaml creation/modification without needing to understand the .xts yaml file format.

Acceptance Criteria

• The XTS CLI provides a straight-forward way to modify .xts yaml files
• The XTS CLI provides a similarly straight-forward way to create new .xts files

[Ulrond]

Not clear if this would be required, everyone can actually read and edit xts files and they should know how todo it.