* feat: support condition field to determine whether a step should be shown
* feat: add support for overriding the hint text using the field 'hint' from the step tiddler
* fix: roll back tour display procedure for now until an override mechanism has been discussed
* fix: renamed advance-criterion field and associated variables to step-success-filter
* fix: renamed hint field to hint-text and selector to hint-selector
* refactor: to create function to get all tour tiddlers filtered by their condition field
* refactor: rename globals tiddlers to variables and avoid making any of the tour procedures global
* fix: also rename globals.tid file to variables.tid
* docs: cover all tour steps tiddler fields
* fix: improve spacing in Tour HUD
