[v1.9.0] New matching strategy variant: `frequency`

[Clémentine]

Related to meilisearch/integration-guides#301

Explanation of the feature

Introduction of a new variant of the matchingStrategy search parameter: frequency. Previous existing ones: all and last

Usage: https://meilisearch.notion.site/frequency-matching-strategy-89868fb7fc584026bc56e378eb854a7f

TODO

• Ensure the matchingStrategy search parameter (in the search method) can accept the frequency value
• Add tests

⚠️ Make PRs pointing to bump-meilisearch-v1.9.0 and NOT main. Please do 1 PR for all of these changes, and not several.

[Clémentine]

Closed by #1670