Add missed blocks charts

[v4lproik]

This is an updated version of the Validator Monitor dashboard including the changes from this issue.

Changes:

• I switched to rows as it's easier to see differences when updating a dashboard according to the same scheme version you used for the beacon processor v2 (eg. v38).
• Added 3 new graphs that get filled out once a missed block is being detected.

Illustrations:

• You can see some illustrations here.

[AgeManning]

Seems to be conflicts now. Does this still function as expected?