Add initial governance guidelines (#1372)

### Summary
> Describe your changes.

Per cncf/sandbox#135, including governance
guidelines.

Signed-off-by: Alex Chantavy <[email protected]>

Author: Alex Chantavy

GOVERNANCE.md

@@ -0,0 +1,16 @@
+# Process for becoming a maintainer
+Generally, express interest. This usually includes things like:
+- Contributing 2+ PRs to Cartography.
+- Regularly participating in discussion on GitHub, on Slack, or in our live video meetings.
+
+# Maintainer responsibilities
+- Hang out on Slack; delayed response is perfectly acceptable
+- Triage GitHub issues and perform pull request reviews for other maintainers and the community.
+- Deeply understand the project's best practices and development patterns.
+
+# When does a maintainer lose maintainer status
+- If a maintainer is no longer interested or cannot perform the maintainer duties listed above, they should volunteer to be moved to emeritus status.
+- If we do not hear from you in over a year, we may remove you from maintainer status without notice.
+
+# Conflict resolution
+We handle conflicts on a case-by-case basis. In general, let's talk it out (Slack, video call, etc). For larger issues we may need to involve more people to come to a decision.