ICSHWI-11797: Remove PV exporter

After discussion from https://jira.esss.lu.se/browse/ICSHWI-11797, we have opted to remove the PV exporter. We will revisit this in the future if there is an appropriate need for it.

Note that this allows us to better support different require versions as no reference to PV names is made as we no longer export PV values.