CHEF-29350 - Replace CONTRIBUTING.md file with standard template for Online-Service

[Saburesh07]

Replace CONTRIBUTING.md file with standard template for online-service This pull request replaces the existing CONTRIBUTING.md file with the standard template for the online-service project. As part of the repo standardization effort we are replacing all the different contributing guides with a standard template that links to a published version of the chef-oss-practices repo. This PR is intended to be a mere mechanical change, not a change in policy. Watch chef/chef-oss-practices for changes in policy. The link provided in the template may not function at the time this PR is opened, in which case this PR is intended to remain in Draft status if the repo permits; in any case it should not be merged until the link is live.

[sonarqubecloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

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