Remove no longer existing Nova/Placement meetings

When the Placement project went back to the Nova community, we no longer had
a placement meeting [1].
Also, we stopped to have an Asian meeting every month in 2021 [2] since
no contributors were there.

[1] https://meetings.opendev.org/meetings/placement/2019/
[2] https://meetings.opendev.org/meetings/nova_extra/2021/

Change-Id: Ic639fa006f4ffbdc4e891d443e25f5e293e4f681

meetings/nova-extra-team-meeting.yaml

@@ -1,12 +0,0 @@
-project:  Nova Monthly Asia Friendly Team Meeting
-meeting_id: nova-extra
-agenda_url: https://wiki.openstack.org/wiki/Meetings/Nova
-schedule:
-  - time:       '800'
-    day:        Thursday
-    irc:        openstack-nova
-    frequency:  first-thursday
-    start_date: 20210603
-chair: Sylvain Bauza (bauzas)
-description:  >
-  This is a monthly extra Nova team meeting in an Asia + EU friendly timeslot.

meetings/placement-team-meeting.yaml

@@ -1,13 +0,0 @@
-project:  Placement Team Office Hour
-meeting_id: placement
-agenda_url: https://wiki.openstack.org/wiki/Meetings/Placement
-schedule:
-  - time:       '1500'
-    day:        Wednesday
-    irc:        openstack-placement
-    frequency:  weekly
-    start_date: 20190605
-chair:  Chris Dent (cdent)
-description: >
-  This is the weekly Office Hour for discussions about Placement and related
-  projects.