Gns3fy

**Fix:**

- Dependency of python to start at version 3.6

**New features:**

- Added `get_file` and `write_file` methods to `Node` and `Project`. Useful for interacting with files that reside on the server like README files, `/etc/network/interfaces` file for docker nodes, among other cases

**Fix:**

- A "template not found" message, when creating a `Node` specifiying a missing/wrong template name.

**Enhacement:**

- `tox` for pipeline testing. https://github.com/davidban77/gns3fy/pull/15
- `projects_summary` and `templates_summary` methods for `Gns3Connector`. https://github.com/davidban77/gns3fy/pull/17
- Improved `nodes_inventory` method. https://github.com/davidban77/gns3fy/pull/23
- Refactor of `Node` creation, basically changed the API endpoint from Node to Template. https://github.com/davidban77/gns3fy/pull/27

**New features:**

- Ability to create `Project`, `Node` and `Link` instances
- Created most of the methods to interact with the REST API Endpoints.
- Added some commodity methods like `nodes_summary`
- Created the `docs`
- Improved the tests and coverage
- Added CircleCI with the following checks:
- flake8
- black formatting
- pytest