Add the option to ignore whitespace changes

[motatoes]

Currently digger performs a plan when any files are changed in a project directory and even if the change only consists of newlines or whitespace. This can lead to alot of noise especially if there is some terraform fmt auotmation being applied in PRs and onto a new project

Proposing to add a digger.yml configuration called ignore_whitespace that makes digger ignore any whitespace changes projects and only trigger on modified projects with non-whitespace changes.