Implement alerting for build times trends changes on Buildbot

Wlad recently discovered that the build time on windows drastically increased, see: https://buildbot.mariadb.org/#/builders/234?numbuilds=4000 . then "build times" tab.

By querying the Buildbot DB (on the replica probably to not load the production), we could pull all the build time metrics and then do some alerting based on history or trend functions:

• https://www.zabbix.com/documentation/6.0/en/manual/appendix/functions/history
• https://www.zabbix.com/documentation/6.0/en/manual/appendix/functions/trends