Preprod to main for feature release v1.6.3

[loleg]

This PR adds the feature of placeholder nodes #531
You can now add non-functional nodes with free text to your workflows. These can for prototyping and designing workflows, to bookmark locations of actual nodes that are later developed, or used as "comments" to explain parts of the workflow.

Screenshot of the workflow editor

Includes fixes from #514

1. fix redirect for bookmarked links
2. update i18n link to handbook
3. fix e2e test cases

Updates:

• Bump github.com/labstack/echo-contrib from 0.15.0 to 0.16.0 #528

[loleg]

Think the unit test should just include the redirect:

 1 failing

  1) User signup & login at http://localhost:1323
       User creation
         profile
           should remove account and logout when clicking again:

      Timed out retrying
      + expected - actual

      -'http://localhost:1323/login?redirect=%2Fadmin%2Fworkflow'
      +'http://localhost:1323/login'
      
      at Context.eval (http://localhost:1323/__cypress/tests?p=cypress/integration/1_user.js:993:18)

[loleg]

OK, that fixed it. There is still a confusing error on the coverage test:

ok      github.com/ProxeusApp/proxeus-core/service      0.048s  coverage: 0.4% of statements in , github.com/ProxeusApp/proxeus-core/main, github.com/ProxeusApp/proxeus-core/main/app, ...
make: *** [Makefile:162: test] Error 1

Exited with code exit status 2