feature: UI enhancements for unconfirmed transactions flow

[comountainclimber]

What current issue(s) from Trello/Github does this address?
This PR is part II of #1766 and provides some subtle updates to the UI to help users understand the exact state of their unconfirmed transactions.

What problem does this PR solve?
Further improves our send UX

How did you solve this problem?
By extending the work started in #1766

How did you make sure your solution works?
Manual testing locally

Are there any special changes in the code that we should be aware of?
I updated addPendingTransaction to always return the retrieved information from the blockchain when adding a tx to storage so that the SideBar can know about only transactions returned from getRawTransaction  as opposed to every transaction that gets added to storage.

Is there anything else we should know?

• Unit tests written?

[coveralls]

Pull Request Test Coverage Report for Build 5630

• 7 of 35 (20.0%) changed or added relevant lines in 5 files are covered.
• 3 unchanged lines in 3 files lost coverage.
• Overall coverage decreased (-0.08%) to 40.045%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
app/components/Send/SendPanel/ActivityLink/ActivityLink.jsx	1	2	50.0%
app/components/Send/SendPanel/SendError/index.jsx	0	1	0.0%
app/containers/App/Sidebar/index.js	1	2	50.0%
app/actions/pendingTransactionActions.js	4	29	13.79%

Files with Coverage Reduction	New Missed Lines	%
app/modules/transactions.js	1	10.11%
app/actions/pendingTransactionActions.js	1	15.46%
app/actions/nodeStorageActions.js	1	72.29%

Totals
Change from base Build 5588:	-0.08%
Covered Lines:	1071
Relevant Lines:	2439

---

💛 - Coveralls