(chore) Setup prettier

[denniskigen]

Requirements

• This PR has a title that briefly describes the work done, including the ticket number if there is a ticket.
• My work conforms to the OpenMRS 3.0 Styleguide and design documentation.
• My work includes tests or is validated by existing tests.

Summary

In this PR, I've added Prettier to this repository as well as eslint-config-prettier. I've also added a task to the package.json file that automatically runs Prettier when a commit is made.

[ibacher]

Cannot find module '/home/runner/work/openmrs-ngx-formentry/openmrs-ngx-formentry/.yarn/releases/yarn-3.6.3.cjs

I think we need to modify .gitignore to include the Yarn exclusions since this also looks like its converting us to Yarn 3.

[denniskigen]

Was it not already running Yarn 3? @ibacher. From my local copy, it appears to be running v3.6.2 (I checked after switching to main and running git clean -xdf). I suspect I may have just bumped the berry version to the latest stable release. And good spot, I missed out on adding the relevant entries to .gitignore.

[ibacher]

Going from here, I think we were using Yarn v1. I'm very happy to update though!

[denniskigen]

Ah, I see. Thanks for clarifying. I will push a commit decoupling the upgrade from this PR.