Feature: Add `extra_delete` option: rm files after sync

[nyetsche]

This PR implements the option to each module of a list of files to delete after the copy into the local directory.

The use case is repositories/modules with "unwanted" information. In our environment all modules downloaded with r10k are checked into our main Puppet git repository. We want to skip files in our repo that we don't need, and do so in a repeatable way.

Example Puppetfile with this feature:

mod 'puppetlabs-cron_core',
  type:    'forge',
  version: '1.2.0',
  extra_delete: ['.github', 'locales', '*/README_*.md', ]

This downloads puppetlabs-cron_core, then removes the directory .github, the directory locales, and the glob */README_*.md.

The module on filesytem without this option:

original
└── cron_core
    ├── CHANGELOG.md
    ├── CODEOWNERS
    ├── LICENSE
    ├── README.md
    ├── REFERENCE.md
    ├── data
    │   └── common.yaml
    ├── hiera.yaml
    ├── lib
    │   └── puppet
    │       ├── provider
    │       │   └── cron
    │       │       ├── crontab.rb
    │       │       └── filetype.rb
    │       └── type
    │           └── cron.rb
    ├── locales
    │   ├── config.yaml
    │   ├── ja
    │   │   └── puppetlabs-cron_core.po
    │   └── puppetlabs-cron_core.pot
    ├── metadata.json
    ├── pdk.yaml
    └── readmes
        └── README_ja_JP.md

11 directories, 16 files

The module on the filesytem with this option as show above:

excluded
└── cron_core
    ├── CHANGELOG.md
    ├── CODEOWNERS
    ├── LICENSE
    ├── README.md
    ├── REFERENCE.md
    ├── data
    │   └── common.yaml
    ├── hiera.yaml
    ├── lib
    │   └── puppet
    │       ├── provider
    │       │   └── cron
    │       │       ├── crontab.rb
    │       │       └── filetype.rb
    │       └── type
    │           └── cron.rb
    ├── metadata.json
    ├── pdk.yaml
    └── readmes

9 directories, 12 files

This option uses Dir.glob for matching: https://ruby-doc.org/core-2.6.3/Dir.html#method-c-glob

If a directory is listed, the entire directory is removed: (rm -rf).

Not setting extra_delete: ... is equivalent to extra_delete: [], which will cause no files to be deleted.

[CLAassistant]

All committers have signed the CLA.

[dbarrous]

This would be such a great feature to have!

[github-actions[bot]]

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