feat: Added Code of Conduct

[colinmurphy]

Created a code conduct as part of #94

For reference reviewed the following examples:

Gatsby - https://www.gatsbyjs.com/contributing/code-of-conduct/ (linked from https://github.com/gatsbyjs/gatsby/blob/master/CODE_OF_CONDUCT.md)

WP GraphQL - https://github.com/wp-graphql/wp-graphql/blob/develop/.github/CODE_OF_CONDUCT.md (note that this makes a tab on the project page)

Symfony - https://symfony.com/doc/current/contributing/code_of_conduct/code_of_conduct.html (linked from https://github.com/symfony/symfony/blob/7.3/CODE_OF_CONDUCT.md)

Github Open Source - https://github.com/github/opensource.guide/blob/main/CODE_OF_CONDUCT.md (note - https://opensource.guide/code-of-conduct/)

[colinmurphy]

@moonmeister @josephfusco @theodesp

Marking this ready for review. The only part I am not sure on is the email address.

[moonmeister]

I think we just need that email. if we want to merge this before getting a new one [email protected] is probably the move. or we wait for @martinmcdonnell to get us one.

[moonmeister]

LGTM!!!

[colinmurphy]

@josephfusco @moonmeister @theodesp

Can you review again please. Updated the email address to [email protected]