introduce Credentials

src/main/python/ddadevops/infrastructure/release_mixin/infrastructure_api.py

@@ -230,13 +230,4 @@ class GitApi():
     def checkout(self, branch: str):
         return self.execution_api.execute(f'git checkout {branch}')
 
-class EnvironmentApi():
 
-    def __init__(self):
-        self.environ = environ
-
-    def get(self, key):
-        return self.environ.get(key)
-
-    def set(self, key, value):
-        self.environ[key] = value