feat: add support for HAS_IS_REMOTE and IS_REMOTE spans and span links

[mmanciop]

Which problem is this PR solving?

Proof of Concept for implementing support for the HAS_IS_REMOTE and IS_REMOTE span and span link flags.

Short description of the changes

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• Added tests to the tracer
• Manually verified flags get sent to a collector

Checklist:

• Followed the style guidelines of this project
• Unit tests have been added
• Documentation has been updated