Maintainability Roadmap

A potential roadmap to improve maintainability, ending with the archiving of this repo.

## TypeScript
- [ ] Update `SwaggerBreakingChanges` in `openapi-alps` to call `npm exec --no oad` instead of `@azure/oad@~0.10.6`
- https://github.com/Azure/openapi-diff/issues/309
- [ ] Move code to `azure-rest-api-specs` repo, folder `eng/tools/openapi-diff`
- [ ] Align deps and config with `typespec-validation`, add to `eng/package.json`
- [ ] Upgrade all dependencies to latest
- If some are really difficult we can choose to stay back, but anything older than latest is a liability
- [ ] Remove .NET code from package, replace with call to nuget/dotnet to install and run separate .NET package
- [ ] Existing CLI name `oad` seems good and short, and aligns with `tsv`
- But could rename cli to `openapi-diff` to be more descriptive
- [ ] Deprecate npm package `@azure/oad`

## .NET
- [ ] Move code to `azure-sdk-tools` repo, folder `tools/openapi-diff`
- [ ] Rename to `Azure.Sdk.Tools.OpenApiDiff`
- [ ] Align deps and config from a similar existing tool, perhaps `http-fault-injector`
- [ ] Publish nuget package and/or dotnet tool to devops nuget feed (similar to `http-fault-injector`)
- [ ] Could **potentially** move code to `azure-rest-api-specs`, and compile dynamically
- But it would be the first .NET code in the repo
- It would add a dependency on .NET SDK (rather than just .NET runtime)

## Docs
- [ ] Move docs to `azure-rest-api-specs` repo

## Final
- [ ] Archive this repo (`Azure/openapi-diff`)