feat: add .nvmrc and .npmrc files

[M-DEV-1]

Description

This PR fixes #6229

Notes for Reviewers

Node.js versions are generally backward compatible but without standardization, inconsistencies in versions can lead to dependency and build issues.

This PR adds a .nvmrc and .npmrc files to standardize the Node.js (and npm) versions.

Signed commits

• Yes, I signed my commits.

[M-DEV-1]

I used package-lock.json and ran commands to filter and return the Node.js version to use. I manually verified this too.

After switching to this version, I ran all necessary setup commands (make lint, make setup, make site, gatsby develop, gatsby build). Everything executed successfully without errors.

[M-DEV-1]

Also, while running make lint

I'm encountering this,

/layer5/src/sections/Company/Contact/index.js
  10:8  warning  'ContactForm' is defined but never used. Allowed unused vars must match /React/u  no-unused-vars

/layer5/src/sections/General/Faq/index.js
  23:8  warning  'ContactFormModal' is defined but never used. Allowed unused vars must match /React/u  no-unused-vars

✖ 2 problems (0 errors, 2 warnings)

Should I comment them out since they are not being used, or should I leave them as it is?

[l5io]

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[l5io]

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[l5io]

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[l5io]

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