- Created a very simplified implementation and a unit test

Co-authored-by: thomashampson <thomas.hampson@stfc.ac.uk>
Co-authored-by: Jonathan Haigh <jonathan.haigh@stfc.ac.uk>

- I made the change because header files from DataHandling could not be imported into files in the API, due to DataHandling being missing from target_link_libraries in the CMakeLists.txt API file. Trying to fix this causes a circular dependency.

Co-authored-by: thomashampson <thomas.hampson@stfc.ac.uk>
Co-authored-by: Jonathan Haigh <jonathan.haigh@stfc.ac.uk>

Co-authored-by: thomashampson <thomas.hampson@stfc.ac.uk>
Co-authored-by: Jonathan Haigh <jonathan.haigh@stfc.ac.uk>

- Added section to look for files in hard coded Linux path
- Changed search function to use relative paths
- Corrected unit test

Co-authored-by: thomashampson <thomas.hampson@stfc.ac.uk>
Co-authored-by: Jonathan Haigh <jonathan.haigh@stfc.ac.uk>

- The name of the directories in the cache uses the extended version i.e. 'MARI' instead of 'MAR', changed the function to account for this
- Changed split into instr and run to handle edge case of 'SANS2D' (digit in instrument name)

Co-authored-by: thomashampson <thomas.hampson@stfc.ac.uk>
Co-authored-by: Jonathan Haigh <jonathan.haigh@stfc.ac.uk>

- Function getInstrument() in the ConfigService is used to retrieve the instrument info from a string argument.
- The argument of the function is either the name or short name of the instrument
- Added option to pass the name or short name + delimiter and retrieve the correct instrument

Co-authored-by: Jonathan Haigh <jonathan.haigh@stfc.ac.uk>

- Added unit test for case when there is a delimiter between instrument name and run number
- Also checks that short name `PG3` gets properly expanded to `POWGEN`

Co-authored-by: Jonathan Haigh <jonathan.haigh@stfc.ac.uk>

- Added some fail proof checks
- Added unit tests for these cases

Co-authored-by: Jonathan Haigh <jonathan.haigh@stfc.ac.uk>

- Added a test class that creates a dummy directory with the same structure as the data cache and performs unit tests on the path outputs
- Introduced safety checks in ISISInstrDataCache to cover for edge cases
- Added the data cache path to Mantid properties file

Co-authored-by: Jonathan Haigh <jonathan.haigh@stfc.ac.uk>

- When user does not have access permissions to a folder, it will print an error informing the user

Co-authored-by: Jonathan Haigh <jonathan.haigh@stfc.ac.uk>

- Deleted unecessary changes that I had made
- Replaced instrument finder by one that already accounts for delimiters and other edge cases
- Removed unecessary notice()

Co-authored-by: Jonathan Haigh <jonathan.haigh@stfc.ac.uk>

- Added datacachesearch.directory to properties file documentation

Co-authored-by: Jonathan Haigh <jonathan.haigh@stfc.ac.uk>

Co-authored-by: Jonathan Haigh <jonathan.haigh@stfc.ac.uk>

- Organized catching of exceptions for bad inputs
- Added check for when user does not have permission to open directory
- Changed logging from notice level to debug level

Co-authored-by: Jonathan Haigh <jonathan.haigh@stfc.ac.uk>

- Made a quick fix for the getInstrument function, to make it throw the exception instead of using a default value
- Not proud of this fix, but when I tried to take out the exception handling out of getInstrument, a few other things were breaking

Co-authored-by: Jonathan Haigh <jonathan.haigh@stfc.ac.uk>

Co-authored-by: Jonathan Haigh <35813666+jhaigh0@users.noreply.github.com>

Co-authored-by: Jonathan Haigh <jonathan.haigh@stfc.ac.uk>

Co-authored-by: Jonathan Haigh <jonathan.haigh@stfc.ac.uk>

Co-authored-by: Jonathan Haigh <jonathan.haigh@stfc.ac.uk>

Co-authored-by: Jonathan Haigh <jonathan.haigh@stfc.ac.uk>

Co-authored-by: Jonathan Haigh <jonathan.haigh@stfc.ac.uk>

Co-authored-by: Jonathan Haigh <jonathan.haigh@stfc.ac.uk>
Co-authored-by: Caila Finn  <caila.finn@stfc.ac.uk>

Co-authored-by: Jonathan Haigh <jonathan.haigh@stfc.ac.uk>

Co-authored-by: Jonathan Haigh <jonathan.haigh@stfc.ac.uk>

Co-authored-by: Jonathan Haigh <jonathan.haigh@stfc.ac.uk>

Co-authored-by: Jonathan Haigh <jonathan.haigh@stfc.ac.uk>

Co-authored-by: Jonathan Haigh <jonathan.haigh@stfc.ac.uk>

Co-authored-by: Jonathan Haigh <jonathan.haigh@stfc.ac.uk>

Co-authored-by: Jonathan Haigh <jonathan.haigh@stfc.ac.uk>

- Check for permission denied is now done inside the loop that directly tries to access files
- Added check for non existing parent directory
- Improved error message when file is not found whithin parent directory

Co-authored-by: Jonathan Haigh <jonathan.haigh@stfc.ac.uk>

- If for some reason the index file on IDAaaS is currupted (eg. being updated) then the error is caught
- Allows for the search to continue on the archive

Co-authored-by: Jonathan Haigh <jonathan.haigh@stfc.ac.uk>

Co-authored-by: Jonathan Haigh <jonathan.haigh@stfc.ac.uk>