CHORE: Updates ember-try and code ready

[abhilashlr]

• [x] This PR adds ember-try with 3.4 and 3.8
• [x] This PR will close #305
• [x] This PR updates integration test to newer qunit-dom and async-await conventions, thereby closing #306

[abhilashlr]

@sbatson5 Seems like the tests are PASS. I am still unsure if run.later is the right way to solve the component integration test case.

[sbatson5]

Thanks for all the work @abhilashlr. I left one more comment.

Also, we try to maintain a clean git history with 1 commit per PR (when possible). Merge commits are actually disabled, meaning we prefer to squash and merge. When updating a branch, we prefer rebasing for that reason, rather than merging master in, as it obscures the history a bit.

Not a huge deal, but for future PRs, rebasing would be preferred.

[abhilashlr]

Merge commits are actually disabled, meaning we prefer to squash and merge.

Squash commits would merge all of them into 1 commit, isn't it?

Not a huge deal, but for future PRs, rebasing would be preferred.

I made 3 PRs at a time and messed up the commits in my fork. Should be fine in the next set of PRs if any👍 .