Rename Razor.Evolution

[rynowak]

We need to come up with an ahem professional-sounding name for Microsoft.AspNetCore.Razor.Evolution.

Suggestions from the previous discussion thread:
Microsoft.AspNetCore.Razor.Engine
Microsoft.AspNetCore.Razor.Parser

My cool suggestions:
Microsoft.AspNetCore.Razor.Compiler
Microsoft.AspNetCore.Razor.Language

I'm hoping to still park most of the important types in the Microsoft.AspNetCore.Razor namespace.

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Names we can't use
Microsoft.AspNetCore.Razor - there are runtime bits here
Microsoft.CodeAnalysis.Razor - we decided against this because we don't want to bring in other Roslyn dependencies at this level.

[rynowak]

/cc @DamianEdwards

[rynowak]

This deserves every label we can throw at it.

[rynowak]

We decided on Microsoft.AspNetCore.Razor.Language