Standardize file locations for supporting files

[sean-zheng-amazon]

Coming from opensearch-project/opensearch-plugins#127.

We should standardize the file location across plugins by implementing following conventions:

• All supporting files for plugins should stay within the plugin's own folder: /plugins/my-plugin
• Within plugin's folder, we recommend following directory structure:
  • ./config: config files
  • ./bin: executables
  • ./lib: for plugins that use native libraries (e.g. libKNNIndexV2_0_11.so)
  • ./install: scripts called to bootstrap the plugin before first use.
  • ./docs: document files
  • ./certs: certificates for the security plugin
  • ./data: test/demo data
• All scripts should come in *nix and .bat flavors, should use OpenSearch's defaults for environment variables like $JAVA_HOME, so users can override these but don't need to specify them by default. Scripts should have 0755 permissions by default.

[peternied]

We've had some concerns about making this change, voiced them in the main issue. I'll deep dive into this tomorrow to see what's feasible for the libs/config/bin alignment

@.sean-zheng-amazon we have been looking into this from the security plugin, it is going to break a large amount of our documentation / related to change the tooling paths that we have used for the audit/hash/securityadmin scripts.

This does not seem high value for the breaking change. Rather than centralize these scripts, what about creating an OpenSearch Admin tool that abstracts these paths entirely? FYI @.setiah that has been looking into this concept.

[peternied]

For 2.0.0 we will complete this task for all folder except for bin, PR is in process now.