📐 Adopt a stricter linter ruler (raywenderlich)

[brunoocasali]

trafficstars

It seems that https://github.com/raywenderlich/swift-style-guide is a linting set of rules that the swift community adopted.

Running locally in it found Done linting! Found 894 violations, 6 serious in 54 files. The proposal is to adopt this style guide in 5 steps:

• [x] Open the PR with the configuration (but as a draft, it should be merged only after step 4) https://github.com/meilisearch/meilisearch-swift/pull/236
• [x] 1. Add the new configuration to CI https://github.com/meilisearch/meilisearch-swift/pull/236
• [x] 2. Fix automatically correctable offenses https://github.com/meilisearch/meilisearch-swift/pull/237
• [ ] 3. Fix other small offenses (one kind per PR?)
• [ ] 4. Ignore the error offenses and create separated issues for them