Add cloud touch points on SDKs/Integrations repos README

[gmourier]

Following meilisearch/mini-dashboard#441 initiative, we could insert touch points for the cloud in every SDKs/Integrations README files to raise awareness.

• We could add a section before/after the "Contributing" section so it's not invasive
  • That section could be fueled with the same message and link of #441
  • We can set the &utm_source= query parameter per SDKs/Integration in the link
• Add a "Meilisearch Cloud" link to the top banner; (same link as the one contained in the dedicated section)

e.g

Section Example

Top Header Example

cc @mayasssh, @davelarkan

[brunoocasali]

I've generated a link like this: https://www.meilisearch.com/pricing?utm_campaign=oss&utm_source=integration&utm_medium=meilisearch-dart to each repository.