Add custom 404 page

[BobanL]

PULL REQUEST

Summary

• Create custom 404 page
  • Using next-js
• Update error handling on view-data
• Make changes to Back button to allow for customization and it was a little bit off center 🤏

Related Issue

Fixes #2850

Acceptance Criteria

• When a user encounters a 404 this page is displayed
• In non-integrated mode, a button is displayed that returns the user to the eCR library
• In integrated mode there is no button

Additional Information

404 Page:

Back button on /view-data
before:

now:

Checklist

• If this code affects the other scrum team, have they been notified? (In Slack, as reviewers, etc.)

[BobanL]

@ashton-skylight - ready for review!

[ashton-skylight]

This looks great, Boban! Two minor changes that weren't reflected in the design, but might create more visual continuity:

1. Change the 404 button text to "Back to eCR Library"
2. On the 404 page, modify the spacing between the blue box and the button to be 24 or 32 px. It needs a little more breathing room