Submit Bounty

**User Story:**
As a funder
I want to be able to see a rendering preview of my bounties detail page
So that i have confidence in what i am posting and how it will look to contributors

**Acceptance Criteria**

**Submit Bounty**
GIVEN i am viewing the preview of my bounty details page
WHEN i click the submit button
THEN i will see a spinner while the system tries to post the bounty
AND the submit button should be disabled while the request is being processed, preventing users from submitting dups
AND once the bounty is submitted successfully i will be navigated to the bounty details page that i just created
AND i will see a success toast message letting me know the bounty was created successfully

**Previous**
GIVEN i am viewing the preview of my bounty details page
WHEN i click the previous button
THEN i will be taken to the step before the preview
AND the data that was previoiusly entered on that step should persist

**Product & Design Links:**
https://www.figma.com/file/8AFLrc4dx9xnMXUkWOAaAR/Existing-Bounties-Updates?node-id=33%3A1854