Inlay hint for screenshot validation calls

[picimako]

Summar of scope

Add inlay hints at end of Terra screenshot validation calls.

Solution details

• Add an inlay hint at the end of line after screenshot validation calls.
• The hint would show
  • the name of the screenshot that is referenced by that call
  • the CSS selector from the wdio.conf.js if it is not defined explicitly in the validation
• Add a Settings option to enable/disable the individual hints. By default the screenshot name should be enabled, while the selector disabled.
• Possible extension points:
  • codeInsight.inlayProvider
  • config.inlaySettingsProvider

Out of scope

• N/A

Other information

• https://www.jetbrains.com/help/idea/inlay-hints.html
• https://www.jetbrains.com/help/webstorm/inlay-hints.html

[picimako]

Completed on release branch.