Clean up meetings directory.

Created by: jeremybennett

This now follows the RISC-V standard, meaning it is easy to sort
chronologically.

Files and directories changed:

* meetings/agendas/agenda-11-may-2020.md: renamed as
meetings/2020-05-11-agenda.md
* meetings/minutes/minutes-11-may-2020.md: renamed as
meetings/2020-05-11-minutes.md
* meetings/agendas/agenda-08-jun-2020.md: renamed as
meetings/2020-06-08-agenda.md
* meetings/minutes/minutes-08-jun-2020.md: renamed as
meetings/2020-06-08-minutes.md
* meetings/agendas/agenda-13-jul-2020.md: renamed as
meetings/2020-07-13-agenda.md
* meetings/minutes/minutes-13-jul-2020.md: renamed as
meetings/2020-07-13-minutes.md
* meetings/agendas/agenda-10-aug-a.md: renamed as
meetings/2020-08-10-agenda-a.md
* meetings/agendas/agenda-10-aug-b.md: renamed as
meetings/2020-08-10-agenda-b.md
* meetings/minutes/minutes-10-aug-2020-a.md: renamed as
meetings/2020-08-10-minutes-a.md
* meetings/minutes/minutes-10-aug-2020-b.md: renamed as
meetings/2020-08-10-minutes-b.md
* meetings/agendas/agenda-14-sep-2020.md: renamed as
meetings/2020-09-14-agenda.md
* meetings/minutes/minutes-14-sep-2020.md: renamed as
meetings/2020-09-14-minutes.md
* meetings/minutes/minutes-01-oct-2020.md: renamed as
meetings/2020-10-01-minutes.md
* meetings/agendas/agenda-12-oct-2020.md: renamed as
meetings/2020-10-12-agenda.md
* meetings/minutes/minutes-12-oct-2020.md: renamed as
meetings/2020-10-12-minutes.md
* meetings/agendas/agenda-09-nov-2020.md: renamed as
meetings/2020-11-09-agenda.md
* meetings/minutes/minutes-09-nov-2020.md: renamed as
meetings/2020-11-09-minutes.md
* meetings/meeting-materials: Directory renamed as
meetings/supplementary-materials

Signed-off-by: Jeremy Bennett jeremy.bennett@embecosm.com