Allow configuring additional plugins for Dataplane - Kong Gateway

[programmer04]

Problem Statement

The relationship between an instance of CRD introduced in

• New CRD for custom Kong Plugin installation #378

and instance of Dataplane needs to be established. Extend with an additional field that matches the name of CRD, eg.

• GatewayConfiguration -> spec.dataPlaneOptions.pluginsToInstall
• DataPlane -> spec.pluginsToInstall

src

Kubernetes ConfigMap has to be mounted as a file in the proper paths of Kong Gateway, also environment variables have to be properly configured to make Kong Plugin available for Kong Gateway to use and be configured with KIC's CRD KongPlugin.

What is in the blue box is in the scope of this issue.

In scope are only LUA plugins without additional dependencies. To add them put plugins in a dedicated directory accessible by Kong Gateway and provide it via environment variable KONG_LUA_PACKAGE_PATH (it allows configuration like e.g. "/opt/?.lua;;"). All plugins must be in that directory.
The name of the plugin needs to be added to the variable KONG_PLUGINS (e.g. KONG_PLUGINS=”bundled,myplugin” where ”bundled” enables Kong default, built-in plugins.

References: Gateway docs, KIC docs

Acceptance Criteria

• Plugin can be configured and used
• statuses about attachment are in place
• referenced plugins can't be removed by mistake