Update OSPR bot for OEP-55 metadata

[nedbat]

Once OEP-55 metadata is in repos, the OSPR bot can be more subtle about where and how it comments.

• Use ownership data to determine whether something is an "ospr" openedx/openedx-webhooks#190
• Use ownership data to decide whether to make Jira issues openedx/openedx-webhooks#192
• Conditionally create JIRA issues for pull requests openedx/openedx-webhooks#189 (possibly)