Remove native-agent code

[brianr]

Description of the change

The native-agent directory in this repo contains a proof of concept implementation for gathering local variables from the JVM to attach to the stack trace. This feature wasn't completed and hasn't been in active development in some time, and has since accumulated some security advisories. We hope to continue development in the future, and in the meantime, are removing the code from the main branch.

Reverts https://github.com/rollbar/rollbar-java/pull/169/files#diff-4dfc3a2ac68fe45bbeca66ab48fe1598875545c79494d91dd5d509d7df6c52ef

Type of change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Maintenance
• New release

Related issues

Fixes:

• https://github.com/rollbar/rollbar-java/security/dependabot/3
• https://github.com/rollbar/rollbar-java/security/dependabot/1

Checklists

Development

• Lint rules pass locally
• The code changed/added as part of this pull request has been covered with tests
• All tests related to the changed code pass in development

Code review

• This pull request has a descriptive title and information useful to a reviewer. There may be a screenshot or screencast attached
• "Ready for review" label attached to the PR and reviewers assigned
• Issue from task tracker has a link to this pull request
• Changes have been reviewed by at least one other engineer