Verify plugin conventions as part of the build

Is your feature request related to a problem? Please describe.

We have a number of inconsistent names in our configurations. And recently we added a plugin name with hyphens instead of underscores (#5138).

Describe the solution you'd like

I'd like to have automation in Data Prepper that verifies that plugin names meet our conventions.

I think this could be done by creating a testing project that has built-in unit tests for scanning for plugins and verifying the naming convention. Additionally, we can have this added automatically to all plugin projects in Data Prepper.

To accomplish this, we could have a new project:

data-prepper-plugin-test

We apply it to all plugins by adding something like the following to data-prepper-plugins/build.gradle

https://github.com/opensearch-project/data-prepper/blob/675864d120e8f88deeee2b341254353c827e06de/data-prepper-plugins/build.gradle#L10-L13

Update the above to the following.

subprojects {
    apply plugin: 'data-prepper.publish'
    group = 'org.opensearch.dataprepper.plugins'
    dependencies {
        implementation project(':data-prepper-plugin-test')
    }
}

At this point, the data-prepper-plugin-test will be part of every plugin project. Now, we need to have tests in there.

The project data-prepper-plugin-test can take a dependency on data-prepper-plugin-framework so that it can use ClasspathPluginProvider. We would also need to add a new method to ClasspathPluginProvider to get all plugin names found. It might look somewhat like the following.

Set<String> listPlugins() {
  if (nameToSupportedTypeToPluginType == null) {
    nameToSupportedTypeToPluginType = scanForPlugins();
  }
  return nameToSupportedTypeToPluginType.keySet();
}

New we can write a unit test that list all plugins and verifies that they meet our naming conventions. Some things we should verify:

• They should be all lowercase
• They should have only _ as a special character

One additional change we'd need is some way to override the conventions. Some of our plugins already have some bad conventions. I propose that plugin authors can add a file to indicate ignores. This can go in src/test/resources/org.opensearch.dataprepper.plugin.test.conventions-configurations.yaml. It might look somewhat like the following:

overrides:
  plugin_names: 
    kinesis-data-streams:
      ignore_conventions: [require_underscores]

This would tell the framework to ignore the convention to require underscores for the kinesis-data-streams plugin. We would still perform the other validations on it.

Describe alternatives you've considered (Optional)

Alternative 1: We could create a Gradle plugin in buildSrc which looks for annotations of @DataPrepperPlugin and verifies the name. This would be a good way to verify the plugin names, but would be quite difficult to extend beyond the plugin names to use on the configurations themselves.

Alternative 2: We could try to use Checkstyle to verify the plugin names. This could be quite simple. But, the downside is that it would only cover the @DataPrepperPlugin annotation.

Additional context
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