Adding initial version of sample tab-blazor-leaderboard

[thomyg]

Q	A
Bug fix?	no
New feature?	no
New sample?	yes
Related issues?	no

What's in this Pull Request?

Adding initial version of sample tab-blazor-leaderboard, a demo sample from one of the latest PnP calls.

First PR to this repo. Happy to change things as needed!

[thomyg]

Pinging @BobGerman as I don't see a reviewer on the top right here.

[BobGerman]

Thanks for submitting; it will be great to have a Blazor sample!
However it does not compile. Please fix and resubmit; thanks!

Severity Code Description Project File Line Suppression State
Error CS0103 The name 'ScoringModell' does not exist in the current context TeamsLeaderboard C:\Users\Bob\Documents\source\PR\teams-dev-samples\samples\tab-blazor-leaderboard\Pages\Tab.razor 179 Active
Error CS0103 The name 'ScoringModell' does not exist in the current context TeamsLeaderboard C:\Users\Bob\Documents\source\PR\teams-dev-samples\samples\tab-blazor-leaderboard\Pages\Tab.razor 183 Active
Error CS0103 The name 'ScoringModell' does not exist in the current context TeamsLeaderboard C:\Users\Bob\Documents\source\PR\teams-dev-samples\samples\tab-blazor-leaderboard\Pages\Tab.razor 187 Active
Error CS0103 The name 'ScoringModell' does not exist in the current context TeamsLeaderboard C:\Users\Bob\Documents\source\PR\teams-dev-samples\samples\tab-blazor-leaderboard\Pages\Tab.razor 202 Active
Error CS0103 The name 'ScoringModell' does not exist in the current context TeamsLeaderboard C:\Users\Bob\Documents\source\PR\teams-dev-samples\samples\tab-blazor-leaderboard\Pages\Tab.razor 206 Active