e2e: Add missing Env concept

[nirs]

We are missing the important concept of environment in the e2e framework.

Tests are composed of workload, deployer, repository and environment. We have workloads and deployers, and we read repository details and clusters from the config.

The clusters are kept now in util.Context - we need to rename it and make it available via the test context.

Tasks:

• Move util/config.go to test/config.go
• Move util.context to test/env.go, rename Context to Env
• Add GetEnv to config
• Add Env() to types.Context
• Access cluster client via Context (e.g. ctx.Env().Hub.Client)
• Add Cluster.Name to tests can use the right cluster names instead of fake name ("c1")
  • Initialize from config or fetch from managedcluster resource
• Add Env.Name and log the name of the environment tested