* Remove Hipchat support from Watcher (#39199)
Hipchat has been shut down and has previously been deprecated in
Watcher (#39160), therefore we should remove support for these actions.
* Add migrate note
This deprecates the `xpack.watcher.history.cleaner_service.enabled` setting,
since all newly created `.watch-history` indices in 7.0 will use ILM to manage
their retention.
In 8.0 the setting itself and cleanup actions will be removed.
Resolves#32041
Removes all sensitive settings (passwords, auth tokens, urls, etc...) for
watcher notifications accounts. These settings were deprecated (and
herein removed) in favor of their secure sibling that is set inside the
elasticsearch keystore. For example:
`xpack.notification.email.account.<id>.smtp.password`
is no longer a valid setting, and it is replaced by
`xpack.notification.email.account.<id>.smtp.secure_password`
This adds a configurable whitelist to the HTTP client in watcher. By
default every URL is allowed to retain BWC. A dynamically configurable
setting named "xpack.http.whitelist" was added that allows to
configure an array of URLs, which can also contain simple regexes.
Closes#29937