Improve Assembly docs (dotnet#9679)

* Delete .NET Framework 1.0 note

No longer relevant

* Generalize description for BadImageFormatException

Delete explicit CLR 2.0 references

* Delete note about reflecting on C++ files

This problem become irrelevant with introduction of ASLR in Windows
Vista (2008)

* Move .NET Framework-specific content to be last

* Delete "The assembly is loaded into the application domain of the caller."

* More BadImageFormatException cleanup

* Delete more instance of "loaded into domain of the caller"

* Note that Assembly.Load creates assembly in isolated load context

* FB

* Apply suggestions from code review

Co-authored-by: Genevieve Warren <[email protected]>

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Co-authored-by: Genevieve Warren <[email protected]>

Author: jkotas