[feat] Support Exporter Metadata in providers

[thomaspoignant]

Note

This issue is a parent issue to track progress on the exporter metadata support.

Following this pull request #2930 we can now support extra metadata in the exporters.
We now need to let users of the SDK be able to add metadata on their own.

Requirements

• It should be possible to add new metadata using the providers options in a option called ExporterMetadata (name can change depending in the language).
• Those metadata should be send in the meta field when calling the v1/data/export endpoint.

Progress

• [feat] Support exporter metadata iOS #2942 - PR feat: Support Exporter Metadata go-feature-flag/openfeature-swift-provider#16
• [feat] Support exporter metadata Android #2941 - PR: feat: Support exporter metadata in Android provider #2944
• [feat] Support exporter metadata Web #2940 - PR feat(go-feature-flag): Support exporter metadata in web and server providers open-feature/js-sdk-contrib#1183
• [feat] Support exporter metadata NodeJS #2939 - PR feat(go-feature-flag): Support exporter metadata in web and server providers open-feature/js-sdk-contrib#1183
• [feat] Support exporter metadata Java #2938 - PR feat(go-feature-flag): Support Exporter Metadata open-feature/java-sdk-contrib#1167
• [feat] Support exporter metadata GO #2937 - PR feat: Support Exporter Metadata open-feature/go-sdk-contrib#614
• feat: support exporter metadata in python provider #2976