Fix Partition<Filtered>, add separate sliceByCached for joins, filtered and nested filtered

[saganatt]

Hi @ktf @aalkin

the Join method is a copy of the Table sliceByCached(), and Filtered is a copy of FilteredBase method. The problem is in returning exact O2 table type, what apparently cannot be done without copies or making sliceByCached() a standalone function and changing the UI. I need the exact type so as to use sliceByCached() for faster event mixing, which will come in another PR.

The changes in Partition constructor fix a newly discovered bug in creating Partitions on Filtered. The buggy methods were called when creating Partitions<Filtered> inside process() or calling sliceByCached() on Partitions<Filtered>.

[ktf]

LGTM if it compiles.

[saganatt]

CI errors unrelated, can we merge?