Add success modal for pipeline tour success

What does this MR do?

Congratulates the user after they create a verified ci config pipeline file for the first time coming off the suggest pipeline tour.

Note

No Changelog required since this is behind a feature flag suggest_pipeline

Closes gitlab-org/growth/ui-ux#65 (closed)

Screenshots

Invalid ci config file

Valid ci config file and meeting all conditions

Still frame

Animation

Screen_Recording_2020-02-25_at_9.27.59_AM

Valid ci config file, but not all conditions met as specified below(today's functionality)

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team