Allow per meeting name customization

[costin]

Currently zat relies on the meeting name as the file name but that's typically not always desirable since the meeting might be verbose, contain special chars (spaces, parenthesis, etc) while for storage, there's typically a well defined name pattern that aims to be consistent.

It would be great if the configuration would allow this per meeting declaration:

- name: This is a big meeting
  google: abc
  zoom: 123
  file: wed-meeting.

Potentially the name itself can serve as the template since the zoom matching happens based on the meeting ID. Extra points for allowing some kind of (basic) templating in the option:

- name: {YYYY-mm-dd}_wed-meeting
  google: ...