Deoccupy root's crontab

Put subdomain TLS certificate renewal jobs to a /etc/cron.d/ file with a
name which clearly marks its association.

Unobtrusively clear root's crontab from the remaining job entries.

misc/cron/bluecherry-subdomain-cert-renewal

@@ -0,0 +1,13 @@
+# This file is a part of bluecherry package.
+
+# .---------------- minute (0 - 59)
+# |  .------------- hour (0 - 23)
+# |  |  .---------- day of month (1 - 31)
+# |  |  |  .------- month (1 - 12) OR jan,feb,mar,apr ...
+# |  |  |  |  .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat
+# |  |  |  |  |
+# *  *  *  *  * user-name command to be executed
+*    * */5 *  *   root    certbot renew --config-dir=/usr/share/bluecherry/nginx-includes/letsencrypt/ >/dev/null 2>&1
+*/5  *  *  *  *   root    curl -k https://localhost:7001/subdomainprovidercron >/dev/null 2>&1
+
+# vim: syntax=crontab

misc/postinstall.sh

@@ -419,7 +419,9 @@ case "$1" in
 	        /usr/local/bin/pip3 install pyopenssl --upgrade
 
 		# Install crontabs for subdomain renewal and SSL renewal using certbot
-		crontab -l 2>/dev/null || true; printf "* * */5 * * certbot renew --config-dir=/usr/share/bluecherry/nginx-includes/letsencrypt/ >/dev/null 2>&1\n*/5 * * * * curl -k https://localhost:7001/subdomainprovidercron >/dev/null 2>&1\n" | crontab -
+		install --mode 600 cron/bluecherry-subdomain-cert-renewal /etc/cron.d
+		# Clean root's crontab from entries which we previously put there
+		crontab -l 2>/dev/null | grep -v 'bluecherry\|subdomainprovidercron' | crontab -
 
 
 		nginx -t 2>/dev/null > /dev/null