Add links to phabricator attachments in Jira

[segunfamisa]

Right now, when a phabricator attachment is attached to a sync'ed bug, the comment on Jira does not contain an easy handle to the patch. The comment looks like this:

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To improve this experience and make it easy to navigate to the phabricator link, we would like to:

1. Add the link to the patch as part of the comment
2. If possible, have the patch attachments as remote links on the Jira ticket

[segunfamisa]

I have two draft commits that attempt to implement each of those items above here: #1206

I would like to get early feedback on this work.