AthenaPoolCnvSvc: Simplify PoolWriteConfig
This MR aims to simplify PoolWriteConfig. We configure PoolAttributes uniformly across all files (i.e. in a for-loop instead of independent/duplicate code blocks). If a format has no settings explicitly defined, we use a default one.
Relates to ATEAM-895
Edited by Alaettin Serhan Mete