UI graphs and control

[TeraMika]

This PR covers a wide range of areas relating to UI, graphs, and motor control.

Issues approached

• Closes Motor Controls #4. While there's refinement to be done of the actual LVDT calculation, the calibration etc. is easily addressed in its own issue another time. Right now what's important is that the motor is driven and a readout is taken.
• Closes UI and Configuration Enhancements #10. All of these things are addressed to some extent. Values update when the component is disabled, a demonstrative graph is added (again, the specific values are not important at the moment, but one minute of temperature readings is reasonable). Values now display null when null and otherwise 0 (previously these were evaluated the same way), and rounding is applied to display fields. PID values are now handled in config.
• Monitoring #12 is referenced but not completed in that a graph now exists, but final placements of UI elements and camera image feeds are far from complete.
• Logging #11 has the same story, where a data store ('graph') adapter now exists with a mechanism to write the outputs of a given dictionary to a .hdf5 file of chosen name in the logs/ directory, and create a .txt or .md file for note-taking in the same place. What other data and metadata requires storing is a future discussion.

Other changes

+ Config file
+ Sensible default values (in config file)
+ More initialisation moved from main
+ UI code more readable via tidying, mainly use of components
~ Classes all tidied
~ Modbus logic refactored and moved where possible, dramatically reducing code in PID file
~ Main loop reworked as part of refactor
~ Debug statements hidden behind config variable. May change and may become more readable and/or granular than all-on, all-off

[TeraMika]

This is being PRd now in order to move the software forward. Some smaller hardware is pending but that overcomplicates this branch - better to finalise these changes and add those in their own branch/PR.
After that comes camera integration following a discussion about data paths and triggering, before more work on logging / data handling / synchronisations, UI changes and eventually integration of machine learning feedback integration.