chore(caldav): Add disconnect function
chore(caldav): Add disconnect function

Signed-off-by: Francisco Miguel Biete <1d85ea0d1a60a438fd84497dece37a4d29dd6409@gmail.com>
<fmbiete@gmail.com>

Freeaqingme/Z-Push-contrib,mta59066/Z-Push-contrib,RavenB/Z-Push-contrib,fmbiete/Z-Push-contrib