hugo.silva - Expose TracingIdType and improved generateUUID method by adding paddex and decimal format, so it can propragate correctly the trace context.

[jhssilva]

What does this PR do?

• Add Expose TracingIdType on SDK
• Update DDRum and DdRUm.test: Improved generateUUID method, by adding paddex and Decimal format

Motivation

The UUID being generated wasn't complying with the expectations to generate the trace on RUM.

Additional Notes

• I've tested in the Application with the ids being generated and traces were generated.

Review checklist (to be filled by reviewers)

• Feature or bugfix MUST have appropriate tests
• Make sure you discussed the feature or bugfix with the maintaining team in an Issue
• Make sure each commit and the PR mention the Issue number (cf the CONTRIBUTING doc)
• If this PR is auto-generated, please make sure also to manually update the code related to the change

[jhssilva]

@marco-saia-datadog FYI