[Suggestion] Set the root namespace of Hazel-ScriptCore to "Hazel"

[tadashuai]

Is your feature request related to a problem? Please describe

The default namespace is the project name("Hazel-ScriptCore"), so set it to "Hazel" for the new file.

However, because of the "Source" folder, we have a new issue. Once creating a new cs script in it, the namespace will be Hazel.Source.
The original intention of this suggestion is to not need to modify the namespace after creating a new script, but it make no senses just like this. Perhaps creating a new script directly under the solution is an indescribable way. As for the sub namespace, for example Hazel.UI, then we create the folder named UI at this point.

Describe the solution you'd like

In the Hazel\Hazel-ScriptCore\premake5.lua, add namespace "Hazel" below the project line. Like this:

project "Hazel-ScriptCore"
    . . .
    namespace "Hazel"