consolidate LuisV3 => Luis assembly in LuisV3 namespace

[tomlm]

We had 2 assemblies, Luis and LuisV3, this delta moves LuisV3 into the LUIS assembly but in it's own namespace.

[coveralls]

Pull Request Test Coverage Report for Build 82791

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-1.0%) to 77.265%

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Totals
Change from base Build 82781:	-1.0%
Covered Lines:	7565
Relevant Lines:	9791

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💛 - Coveralls

[carlosscastro]

I wish we didn't use version numbers in assemblies. Given that this already exists and we are just moving it around, approving.

[fuselabs]

✔️ No Binary Compatibility issues for Microsoft.Bot.Builder.dll compared against version 4.5.3
✔️ No Binary Compatibility issues for Microsoft.Bot.Builder.AI.Luis.dll compared against version 4.5.3
✔️ No Binary Compatibility issues for Microsoft.Bot.Builder.AI.QnA.dll compared against version 4.5.3
✔️ No Binary Compatibility issues for Microsoft.Bot.Builder.ApplicationInsights.dll compared against version 4.5.3
✔️ No Binary Compatibility issues for Microsoft.Bot.Builder.Azure.dll compared against version 4.5.3
✔️ No Binary Compatibility issues for Microsoft.Bot.Builder.Dialogs.dll compared against version 4.5.3
✔️ No Binary Compatibility issues for Microsoft.Bot.Builder.TemplateManager.dll compared against version 4.5.3
✔️ No Binary Compatibility issues for Microsoft.Bot.Configuration.dll compared against version 4.5.3
✔️ No Binary Compatibility issues for Microsoft.Bot.Connector.dll compared against version 4.5.3
✔️ No Binary Compatibility issues for Microsoft.Bot.Schema.dll compared against version 4.5.3