Fine grant access rule adjustment - PUBLIC_READABLLE

[tunacicek]

Current State
Currently the list of defined specificAsset Keys (like manufacturerId) in the value.yml is ignored.
It is possible to define a public_readable rule over all specificAssetIds.

• Adjustments*
  The PUBLIC_READABLE Rule is only allowed for the keys which are defined in the externalSubjectIdWildcardPrefix. If a key is not available in this list, the rule needs to be ignored.

[tunacicek]

PR is created:
#418