Feature .net 5 (#5505)

* Update projects to use .NET 5.0, the successor to .NET Core

* Fix ambiguous errors. Add IBAutomator net5

* Remove FXCM

* Upgrade IBAutomater to v1.0.51

ignored, and an empty message aborts the commit.

* Fix rebase

- Fix ambiguous Index
- Remove StrategyCapacity.cs
- Update System.Threading.Tasks.Extensionsy

* Remove unrequired references

* Fixes

- Travis will use dotnet, not nunit nor mono
- Remove mono from foundation image
- Fix python setup in research
- Fix unit tests

* Don't call ReadKey when input is redirected

* Fix ConsoleLeanOptimizer

* Research fixes

* Update comment

* Add vsdbg to Dockerfile

* Fixes

- Revert dockerfile FROM custom changes
- Adjust and fix regression algorithms
   - Option assignment will be deterministic in the order
   - 'Rolling Averaged Population' is calculated using doubles, updating
     expected values.
- Update readme, removing references to mono
- Add missing Py.Gil lock

* Replace ICSharp with .NET Interactive

* Fixes after rebase

* CSharp research fixes

- Adding new Initialize.csx that pre loads all assemblies
- Adjusting template research file
- Moving steps in dockerfilejupyter
- Fix unit tests and regression tests after rebase

Co-authored-by: Gerardo Salazar <gsalaz9800@gmail.com>
Co-authored-by: Stefano Raggi <stefano.raggi67@gmail.com>
Co-authored-by: Jasper van Merle <jaspervmerle@gmail.com>

Algorithm.Python/QuantConnect.Algorithm.Python.csproj

@@ -4,7 +4,7 @@
     <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
     <RootNamespace>QuantConnect.Algorithm.Python</RootNamespace>
     <AssemblyName>QuantConnect.Algorithm.Python</AssemblyName>
-    <TargetFramework>net462</TargetFramework>
+    <TargetFramework>net5.0</TargetFramework>
     <LangVersion>6</LangVersion>
     <AnalysisMode>AllEnabledByDefault</AnalysisMode>
     <OutputPath>bin\$(Configuration)\</OutputPath>