[release-v2.7] Remove logging and monitoring charts

[mallardduck]

A release- targeting version of: #613

RE:

Per recent slack chats, these charts are not necessary for use anymore as all logging and monitoring charts should come from rancher/charts repo for 2.7+; doing a manual verification I cannot find references to indicate that these should be kept around.

If anyone happens to incorrectly still be using these versions then they likely have larger issues than removing this will cause and should opt to update to a version coming from rancher/charts sources. We can likely also backport this to 2.7 as well - though that is less urgent/necessary as that version will go EOL sooner than later.

[nicholasSUSE]

Assuming these charts are not being used by anyone, as per the PR owner.
LGTM.