Packages reorganisation

[guicassolato]

Reorganisation of /pkg

Before	After
pkg/common.auth	pkg/auth
pkg/common/auth_credentials	pkg/auth
pkg/common/auth/mocks/http_mocks	pkg/httptest
pkg/common.json	pkg/json
pkg/common/log	pkg/log
pkg/common.CheckContext	pkg/context
pkg/common.FetchEnv	main.go#fetchEnv
pkg/config	pkg/evaluators
pkg/config#APIConfig	pkg/evaluators#AuthConfig
pkg/cron	pkg/workers

• Always import “github.com/kuadrant/authorino/api/v1beta1" as “api”
  
• Remove missing creds log error

[guicassolato]

Some offline discussion about the packages pkg/httptest and pkg/context. These are essentially abstractions (collections of helpers, really) for other Golang packages (net/http/httptest and context, respectively).

Stuffing those into a helpers package didn't feel right, precisely to avoid repeating a pattern this very PR is getting rid of, i.e. of having generic buckets like "others", "common" and "utils" where all the random stuff we do not know where to put end up going.

"Helpers" is somewhat more specific than the other examples mentioned here, but we decided to be conservative in this iteration, avoiding the generic buckets at all cost. We can always revisit this decision in the future in case we realise we exaggerated by specialising too much and not grouping enough.