Add system account mode to Kogito data index service

Data index needs to be able to use system account to bypass the defined permissions and roles. If the connection is  from an specific user, the security context have to be used instead in communication with the runtimes.

In case that the system account is used we have different options:  the user and groups will be passed as parameter or the runtime itself can be able to perform admin operations from system account. (TBD)