(feature) Support apiKeys in all the available open-feature providers

[thomaspoignant]

Requirements

Since v1.7.0 the relay proxy supports the possibility to add some apiKeys to control who is accessing it. We should be able to configure an apiKey on all available providers.

• [x] GO - https://github.com/open-feature/go-sdk-contrib/pull/166/
• [x] Java - https://github.com/open-feature/java-sdk-contrib/pull/270
• [x] .NET - https://github.com/open-feature/dotnet-sdk-contrib/pull/59
• [x] javascript - https://github.com/open-feature/js-sdk-contrib/pull/310
• [x] Add new integration tests to validate that providers are working with the apiKey - #668

[thomaspoignant]

An issue was found in the Javascript provider, we should wait for this PR https://github.com/open-feature/js-sdk-contrib/pull/317 to be merged and the new version to be released before closing this issue.