3274: Reject master keys that are less than 16 bytes and add `--generate-master-key` CLI option r=irevoire a=dureuill
# Pull Request
## Related issue
Fix#3272Fix#3287
## What does this PR do?
### User standpoint
---
- Adds a `--generate-master-key` CLI flag to generate a fresh Master Key and exit.
<img width="1351" alt="Capture d’écran 2022-12-22 à 14 18 58" src="https://user-images.githubusercontent.com/41078892/209142778-eab52eeb-eaa8-409b-897a-c0d5728c8aaa.png">
---
(relevant fragment of the `--help` message)
<img width="1351" alt="Capture d’écran 2022-12-22 à 14 19 40" src="https://user-images.githubusercontent.com/41078892/209142891-ebfa2ed6-f231-4f76-a3ae-b7542c7aef04.png">
---
- When `meilisearch` is started in the `development` environment and no Master Key has been provided, then the binary prints a warning before starting.
<img width="1351" alt="Capture d’écran 2022-12-22 à 14 14 49" src="https://user-images.githubusercontent.com/41078892/209142158-54eba3b7-bf71-4f3f-8840-0600b13a1a9f.png">
---
- When `meilisearch` is started in the `development` environment and the provided Master Key is shorter than 16 bytes, then the binary prints a warning before starting.
<img width="1351" alt="Capture d’écran 2022-12-22 à 14 15 58" src="https://user-images.githubusercontent.com/41078892/209142295-0209fe47-c03b-424f-a73f-cee9b633137a.png">
---
- When `meilisearch` is started in the `production` environment, and no Master Key is provided, the error message is altered to generate a fresh Master Key.
<img width="1351" alt="Capture d’écran 2022-12-22 à 17 29 02" src="https://user-images.githubusercontent.com/41078892/209180540-0def5798-15db-47f0-a6ec-8cfa081dea77.png">
---
- When `meilisearch` is started in the `production` environment, and the provided Master Key is shorter than 16 bytes, then the binary exits with an error.
<img width="1351" alt="Capture d’écran 2022-12-22 à 17 28 47" src="https://user-images.githubusercontent.com/41078892/209180567-fa54fe33-fbc4-4b9f-b281-7dfb7b33af85.png">
---
This implements the solution B described here: https://github.com/meilisearch/product/discussions/538#discussioncomment-4391346
### Implementation standpoint
- Add a new `meilisearch-auth::generate_master_key` function that uses a Cryptographic Random Number Generator (CRNG) to fill a vector of 32 bytes before encoding these bytes as base64
## PR checklist
Please check if your PR fulfills the following requirements:
- [x] Does this PR fix an existing issue, or have you listed the changes applied in the PR description (and why they are needed)?
- [x] Have you read the contributing guidelines?
- [x] Have you made sure that the title is accurate and descriptive of the changes?
Thank you so much for contributing to Meilisearch!
Co-authored-by: Louis Dureuil <louis@meilisearch.com>
Co-authored-by: Tamo <tamo@meilisearch.com>
We were writing the instance-uid as bytes instead of string in the data.ms and thus we were unable to parse it later.
Also it was less practical for our user to retrieve it and send it to us.
