`astarte_dev_tool`: setup and features

[shinnokdisengir]

astarte_dev_tool first commit

The branch is based on https://github.com/astarte-platform/astarte/pull/956, which is necessary to start docker compose in development mode

Addition of astarte_dev_tool functionalities: the functionalities are stateless and based on the mix task mechanism

• [X] mix astarte_dev_tool.system.up: start docker compose in dev mode
• [x] mix astarte_dev_tool.system.down: stop docker compose in dev mode
• [X] mix astarte_dev_tool.system.watch: watch mode to enable hot-code-reloading

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 69.49%. Comparing base (1a9c203) to head (7230a50). Report is 14 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #978 +/- ## ========================================== + Coverage 67.99% 69.49% +1.50% ========================================== Files 281 267 -14 Lines 7420 6613 -807 ========================================== - Hits 5045 4596 -449 + Misses 2375 2017 -358 ```

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