Similar paths are now compared ignoring casing

[AndreaPiovanelli]

Reference issue: #8742
Added StringComparer and forced lowercase where needed to ensure matching paths to ignore casing.
This changes apply to new content or when autoroute is changed. This means that, for existing content, if user does not change the current url textbox, the path generation is skipped, thus keeping ambiguous paths if present.
For this reason I opened a draft pull request for the moment, to find a way to avoid this ambiguity for existing content. This can be solved mainly in two ways:

1. Forcing the slug / url generation even if the matching between url and content routevaluedictionary is passed (

   Orchard/src/Orchard.Web/Modules/Orchard.Autoroute/Services/AutorouteService.cs

   Line 217 in 9644ced

   if (itemRoute != null

   )
2. Adding a migration step (in Orchard.Autoroute or Orchard.Alias) forcing the regeneration of all ambiguous urls.

[MatteoPiovanelli]

@sebastienros @AndreaPiovanelliLaser should we merge this in, and worry about possible pre-existing path conflicts some other time, since this should prevent any new ones from cropping up?

[sebastienros]

I think you can merge, I approved the PR