fix issue of https://github.com/ysde/grafana-backup-tool/issues/96

This can make it easier to see changes when the backups are compared within version control.

Note, this changes to always pretty-print the JSON.  You might prefer that it's a configurable option.

fix typo

- #83 Fix tarfile options for python2
- #64 Remove empty folders when backup file (.tar.gz) created.

Change x:gz to w:gz for supporting python2

* added config example

This commit introduces the settings option client_cert. It is now
possible to add a file path to a client certificate in the configuration
file or as an environment variable. The default is None.

* **config file:**

```
{
  "general": {
    ...
    "client_cert": "/home/user/.certs/grafana.pem"
  },
  ...
}
```

* **env variable:** CLIENT_CERT

Signed-off-by: Jürgen Löhel <juergen.loehel@inlyse.com>

The folders.txt file previously only contained one folder, even if more than one folder was backed up.

* Remove ability to use yaml for configuration in favor of json
* Remove conf module
* README.me updates

* replaced pathlib with os.path
* added JSON config support

* updated README.md
* fixed missing debug argument for create modules
* updated CHANGELOG.md

* refactored to used positional arguments

* refactored to use positional arguments

* refactored to use positional arguments

* refactored to use positional arguments

* refactored to use positional arguments

* refactoring to use positional statements

* refactored, realized argparse is being used in individual commands...
* added backup Makefile
* removed backup_grafana.sh and restore_grafana.sh
* removed docker_entry.sh
* (Need to update README and CHANGELOG...)
* (Need to add support for --verbose)