closes #4230

Update CHANGELOG.md

Align auto refresh interval

Grafana supports ms resolution for Opentsdb

Add support for pre/post update hooks in the PluginEditCtrl.

This allows users to intercept the update procedure from their own
controller to modify the pluginSettings before they are saved and
perform additional tasks like syncing state via a third party API.

fix(prometheus): fixed templating issue with prometheus for when using variable with non regex operator, #2918

remove forced page header from app pages.

redact settings containing 'secret' besides 'password'

Ensure that settings with the word 'secret' in the name are redacted just
as ones with 'password' in the name are. For example, the Google Auth
client secret should be redacted now.