Fix provider install doc

[ShreyasNBS]

Description

Updated docs and examples to accurately reflect how to test the provider locally.

Motivation and Context

The dev_override option does not work well with terraform init as mentioned here. Hence I spent a few hours reading the docs online and figured out a cleaner way to test out the provider locally which worked well with usual terraform commands (int, plan and apply)

How Has This Been Tested?

I have followed my own instructions detailed in this PR, and I have successfully initialised the terraform provider. Screenshot has been provided below.

Screenshots (if appropriate)

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist

• [x] I have updated the documentation accordingly.
• [ ] I have read the CONTRIBUTING document.
• [ ] I have added tests to cover my changes if appropriate.
• [ ] All new and existing tests passed.

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