New password-reset flow: docs, examples, project template

[bajtos]

• Update https://github.com/strongloop/loopback-example-user-management
  • New password flow and email reverification loopback-example-user-management#58
• Update our documentation to reflect the changes made in Tighten security for resetting password #382. Include a guide showing users how to correctly set up password-related endpoints in LoopBack applications.
  (internal task: https://github.com/strongloop-internal/scrum-asteroid/issues/131)
• Modify the template in loopback-workspace to enable the new, more secure mode
  (internal task: https://github.com/strongloop-internal/scrum-asteroid/issues/132)
• Print a warning when the feature flag is unset, to force users to make a decision whether to upgrade or stay behind.
  (internal task: https://github.com/strongloop-internal/scrum-asteroid/issues/133)
• Announce these changes to our ANN mailing list

[superkhau]

Create new timeboxed story.

[bajtos]

I don't think we will have bandwidth to do this, considering that LB 4.0 has been released.