added contribution markdown file

[codingshot]

example and reference in readme instead of putting in main readme as PR Best Pracice

Contribution Guidelines

We welcome all types of contributions to our project, including but not limited to:

• Suggesting new reference techniques which prioritize smart contract vulnerability detection.
• Adding exploits or slips up and firms that slipped up with reference to their initial audit
• Adding active or (marking old bug programs as deactive)
• Adding additional audits (make sure to reference original audit in table but also upload the pdf of the audit to the Audit folder with the following naming convention YEAR-MONTH-DAY-FIRM-SCOPE-OF-AUDIT.pdf
  Adding additional security firms (note only add the firm from now on if you have also provided an audit firm in the same PR
  Fixing typos and streamlining the categorization process
• Adding additional NEAR Security resources
  -Add more projects that you are asking for audits to
• End to End testing and Appsec reports
  Suggesting improvements to the classification standard
  Correcting mislabeled bug and exploits or descrbing an audit more cleary (For ex; HERE Wallet -> HERE Wallet liquid staking)
• Improvements to contribution guidelines

Format

• Make a PR and make sure to # the close the issue number if relevant

Thank you for your contributions!