Fix "Workflow Transitions" override marking

Again caused by recent regressions from 7094372255c5aa89787cc105c31c9e1f7daa649e

- There was still usage of old config options that were deprecated.
- HTML elements were generated with multiple class attributes.
- When retrieving global configs use ALL_USERS instead of null (default user).

Fixes #17658
Change 'colour' to 'color'

Renamed the variables and function names within the workflow config pages modified in this pull request.
Fix php error for undefined t_workflow variable
Fix showing of workflow transitions

The workflow transition were not being shown due to accessing the wrong variables when rendering the page.

Fixes #17658
Merge pull request #515 from vboctor/Issue17658

Fix "Workflow Transitions" override marking