support terragrunt blocks

[motatoes]

We already have support for blocks: but for terraform projects. I’m thinking that we can adapt the same for terragrunt but additional terragrunt: true flag for those projects. if terragrunt is true then we have common arguments of workflow and workflow_file, but if false then user can use include/include arguments as it used to be for terraform generation

generate_projects
    blocks:
      - block_name: dev
        terragrunt: true
        root_dir: "dev/"
        workflow: default
        workflow_file: digger_workflow_dev.yml
      - block_name: staging
        terragrunt: true
        root_dir: "staging/"
        workflow: default
        workflow_file: digger_workflow_staging.yml

This PR also refactors the functions for gitlab, bitbucket azureDevops since they are all duplicates and we weill be moving to a spec to unify those branches eventually (#1540)