Add option for raft layer(s) filament selection

[bdpdx]

In the current version of BambuStudio, the filament selection option for raft and support base is combined.

I regularly have trouble getting PVA to adhere to my high temperature plate, but have no problem getting it to adhere to PLA.

This PR splits the raft filament and support base filament into separate selectors, and prints the raft base in the selected filament. This lets the user print a PLA raft and a PVA support base on top of it (although any filament can be chosen for the raft).

Here is what the Support dialog looks like with this change:





This is an image of a 1-layer raft using the selected PLA filament:





This is what the support base looks like on top of the raft:

[lanewei120]

Hi @bdpdx

thanks for this patch

please remove the translation files in this patch
we will review the other part

[bdpdx]

please remove the translation files in this patch we will review the other part

done. reverted changes to .pot file also and squashed commits.