Add build log link to attachments

[midpackrunner]

I found myself needing a link to the build log as in this issue.

I added the build number with a link to the build log to the top of the attachments. I also moved the build duration into the attachments to make the message easier to process visually - I hope that's not too presumptuous. This is the output for a build (with no changes):

Thanks for building this! It's incredibly helpful.

[midpackrunner]

Oh, I didn't rev the version since I wasn't sure how you were tracking. So, there's that. Thanks again!

[jasonconnery]

I like the idea of moving the build time to the attachments alright, I may pull that in, but personally I'm not sure I need the build number in the slack message the way we use it. I think for the link to the build I may just make the Project Name clickable.

[midpackrunner]

Fair enough. If I had enough time, I'd love to build out a message customization GUI in TC with some of the most commonly used info. If I ever find the time, I'll send you a PR. ;)

[jasonconnery]

GUI of any sort would be awesome, I didn't have the time myself for a GUI even for the basic config stuff. One day maybe :)

[smckisic]

This build is working great. Thanks! The build log link is a welcome enhancement, and the notifications are more readable.