Allow setting configuration parameters via a config file

[idoavrah]

Discussed in #83

^{Originally posted by remiflament August 13, 2024}
Hello 👋🏻 Thanks for this usefull tool !
Do you have already implemented a configuration file that can be use ? example ~/user/.config/tftui.config

I was looking on a way to store the tftui.plan under the folder .terraform/ despite of the root folder actually use.

Thanks you