(maint) Replace .editorconfig with nuget package

[vexx32]

Description Of Changes

• Remove editorconfig file
• Add gitignore entry
• Install nuget package for the editorconfig file/best practices

Motivation and Context

In order for us to have a consistent baseline for code style, we've pulled our standards out into a Chocolatey.BestPractice nuget package, which is being brought in to here.

Testing

1. Build the project in VS to populate the nuget package and files
2. Verify the editorconfig rules are still being applied by adding or modifying code to cause a violation. (for example, I tested these rules are still in effect by adding a single-line if statement without braces and checking VS's error list to ensure the IDE0011 style rule is flagged as it should be with our editorconfig settings.

Operating Systems Testing

N/A

Change Types Made

• Bug fix (non-breaking change).
• Feature / Enhancement (non-breaking change).
• Breaking change (fix or feature that could cause existing functionality to change).
• Documentation changes.
• PowerShell code changes.

Change Checklist

• Requires a change to the documentation.
• Documentation has been updated.
• Tests to cover my changes, have been added.
• All new and existing tests passed?
• PowerShell code changes: PowerShell v3 compatibility checked?

Related Issue

N/A

[gep13]

LGTM!

[gep13]

@vexx32 thank you for getting this added!