configurable separators for query parts and verbs | use space instead of comma in token search

**Did a discussion occur before?**
No or not sure.

**Is your feature request related to a problem? Please describe.**
I'm trying to use broot to quickly jump to directories in my file tree. My favorite search mode is `: tokens path` because it's very natural for me to filter by several path components, e.g. I'd like a query "chirpy src" to yield the directory `/home/username/dev/company/repository/src/chirpy` (assuming `cwd=/home/username/dev/company`).

The problem is that in "tokens" search mode I have to use comma as separators, e.g. "chirpy,src", which is not very natural for me.

**Describe the solution you'd like**
It would be great if I could configure separators so that I could type "chirpy src" instead of "chirpy,src". I don't really use verbs functionality, but if I did, maybe a different separator could be assigned to indicate a beginning of a verb.

**Describe alternatives you've considered**
I read https://dystroy.org/broot/input/#subtleties but couldn't find the solution there.

Start with the input subtleties documentation linked in the issue and trace the tokens search mode and verb parsing entry points. Define how configurable separators should affect queries such as "chirpy src" and verb beginnings, then verify both configured token searches and existing comma-separated behavior.

Written by the indexing model from the issue text.