refactor: Simplify code on partition_configuration

[acelyc111]

There is no functional changes, but only refactoring, includes:

• Use range-based loop
• Unify the naming of partition_configuration variables to pc (or pcs)
• Use fmt::join for simplify container formating
• Reduce some if-else statements depth

This patch dosen't change the names in thrift IDL which leads more changes on client drivers, we can do that in following patches.