(feat) Lua Scripting for Dynamic Kubernetes Deployments

[gianlucam76]

Sveltos can execute Lua code stored in ConfigMap or Secret resources. To enable this functionality, these resources must be annotated with the projectsveltos.io/lua annotation.

1. Resource Referencing: Sveltos profiles can reference ConfigMap and Secret resources.
2. Lua Code Identification: Sveltos identifies resources with the projectsveltos.io/lua annotation.
3. Lua Code Execution: Sveltos executes the Lua code found within these resources.
4. Deployment based on Output: The output generated by the Lua code is used to deploy configurations to matching clusters.

Sveltos provides helper functions to simplify working with resources:

1. getResource(resources, "resource identifier"): Retrieves a specific
   resource using its identifier from the provided resource list. resources
   represents all Kubernetes resources defined in the Spec.TemplateResourceRefs
   section of a Sveltos profile. identifier must match an identifier previously
   defined in the Spec.TemplateResourceRefs section of the profile.
2. getLabel(resource, "key"): Returns the value of a label with the
   specified key for a given resource.
3. getAnnotation(resource, "key"): Returns the value of an annotation
   with the specified key for a given resource.
4. base64Encode and base64Decode
5. json.encode and json.decode
6. strings functions like Compare, Contains, HasPrefix, HasSuffix, Join,
   Replace, Split, ToLower, ToUpper. We use https://github.com/chai2010/glua-strings
   so full list can be found there. To use those methods strings.ToUpper("mystring")
   for instance

Sveltos allows users to extend its Lua scripting capabilities
by defining custom helper functions. These functions are packaged
as Lua code within a ConfigMap residing in the projectsveltos namespace.
For Sveltos to load and utilize these custom functions, the lua-methods
argument must be provided to the addon-controller deployment. Once loaded,
these custom methods become available whenever Lua code is executed by Sveltos.

This PR uses:

1. https://github.com/chai2010/glua-strings/
2. https://github.com/layeh/gopher-json

Fixes #403