Migrate WMCore/Cache/* to be compatible with both python2 and python3

[mapellidario]

Impact of the new feature

This involves migrating WMCore.Cache.WMConfigCache and WMCore.Cache.GenericDataCache all their dependencies. The dependencies list is obtained with pydeps and is attached at the end of this issue.

Is your feature request related to a problem? Please describe.

Make WMCore.Cache.* compatible with both python2 and python3.

Describe the solution you'd like

Run futurize on WMCore.Cache.* and their dependencies and then apply the necessary manual changes, starting from the lowest-level modules up to the higher level ones.

Additional context

Some more information can be found on our mkdocs documentation

This is the dependency diagram (this cxan be obtained repliocating the instructions about pydeps on dmwm mkdocs documentation )