Cleanup: remove columnworkspace_auto_off from tableorganizations

Add columns to tableworkspace

• autostart_enabled:bool default false
• autostop_enabled:bool default false
• autostart_at:timestamp with time zone default '0001-01-01- 00:00:00+00::timestamptz NOTE: this will include the user’s timezone
• autostop_at:timestamp with time zone default '0001-01-01- 00:00:00+00::timestamptz NOTE: this will include the user’s timezone

Add methods toquerier.go:

• SetWorkspaceAutoStartEnabled(ctx context.Context, workspaceid string, when time.Time) error
• SetWorkspaceAutoStartDisabled(ctx context.Context, workspaceid string) error
• SetWorkspaceAutoStopEnabled(ctx context.Context, workspaceid string, when time.Time) error
• SetWorkspaceAutoStopDisabled(ctx context.Context, workspaceid string) error

Changes:

• Instead of atime.Time, will use a crontab-style representation for schedules. Seecreate cron-style library or wrapper for workspace autostart / autostop #817.
• autostart_at andautostop_at will be renamedautostart_schedule andautostop_schedule respectively.
• autostart_schedule andautostop_schedule will allow NULL values, allowingautostart_enabled andautostop_enabled to be removed.
• We only need theUpdateWorkspaceAutostart andUpdateWorkspaceAutostop methods, passingnil as the schedule can be semantically equivalent toDisableWorkspaceAuto{Stop,Start}.