Update to EPICS7 #4416
Description
As a developer I would like to run EPICS 7 to access the newest features and also avoid technical debt.
Notes: as EPICS 7 includes epics 3 and epics 4 in a new directory structure, adjustments to the IBEX build system may be required. This will include removing our existing EPICS 4 installation and adjusting link on all IOCs using EPICS4, but may extend wider.
Acceptance criteria:
- all IOCS build and tests pass
- run control is modded to allow the PV names to be a waveform and initialised by the block PV name. See GUI: Blocks should be limited in length #3647 and SUPPORT: Runcontrol does not work for certain PVs #4393