Remove the Contribution Guide in B.io

[praneesha]

Purpose

We need to remove the Contribution Guide in B.io[1] and move it to theCONTRIBUTING.MD file.It is because it is a better approach to have separate CONTRIBUTING.md files in each of the Ballerina repos with repo-specific information.

Later, we can have a Contributing Guide in B.io to explain generic information such as the contribution review process etc.

[1] https://ballerina.io/contribution-guide

Fixes #224

Related Issues:
Created #231 to add a Contribution Guide to the B.io later with the appropriate content.

Check List

• Page Addition

  • Add permalink to pages
  • If contains empty folder(s), Add front-matter redirect_to:

• Page Rename

  • Add front-matter redirect_from
  • Add front-matter redirect_to: (If applicable)