Implement CLI commands for serverless module

[kwiatekus]

Description

Implement a set of CLI commands for serverless allowing users for C/R/D operations for Function CRs

> kyma function --help

Description:
  manage functions # description of new commands group

Commands:
  create - create function
  patch - update individual function fields (not all flags must be provided, but only those changed)
  get - get function/s
  delete - delete function

Function creation from local (source and dependencies) files should be possible

> kyma function create --help

Description:
  create function

Flags:
  --name (required)
  --namespace - resource namespace (default: default)
  --runtime, -r - function runtime (default: Nodejs20)
  --replicas - function replicas (default: 1)
  --source - path to file with functions code 
  --dependencies - path to file with functions dependencies

Function can be created w/o passing source and dependency paths. CLI should have advanced defaulting for this case.

AC

• commands (config maps) are part of serverless module
• user should be able to create function from local files (handler and dependency)
• users should be able to create function for all supported runtime types (Node.js and python)
• users do not need to pass path to files; CLI should default the content with minimalistic hello-world like example

Reason
Kyma users are currently using kyma cli v2 commands to apply functions from local files.

Related links
accepted design
prototype