Changed behaviour:

- Minor change to some tests to add Debug flag to ensure that IvsLam outputs that are being checked are actually created. For group workspaces this is currently true anyway at the moment but might not be going forward.

Add new unit tests:

- Check default output names are correct.
- Check that user can override default names.
- Check both with and without debug outputs.

Also fixed ambiguous overload in reflectometry helpers.

Re #24564

Touches some 'obvious' cases where histograms were misused.

- Replace copies by references to x, y and e histogram data
- Use setSharedX, setSharedY, setSharedE instead of manually copying the
values
- std::move vector data to histograms
- Fix off-by-one errors in SaveReflThreeColumnAsciiTest,
SaveReflCustomAsciiTest, SaveANSTOAsciiTest and ISISEnergyTransfer
- Fix issues in RefAxisTest

Re #24462

The instrument/IDFs_for_UNIT_TESTING directory was renamed to instrument/unit_testing, as it now contains nexus as well as IDF files.
All the paths in the source were changed accordingly.

The SMALLFAKE_example_geometry.hdf5 was moved from the build ExternalData to instrument/unit_testing.

The LOKI_Definition.hdf5,SANS2D_Definition_Tubes.hdf5,WISH_Definition_10Panels.hdf5 files were moved
from the build ExternalData to instrument/unit_testing.

(May re-instate old ICAT code as a second, backup searcher, and also need to create one for HFIR instruments with run numbers.)

Update copyright headers in all files

Squashed commit of the following:

* First version of a script to manage copyright statements

re #23468

* Neatened up script, added comments

re #23488

* move script to tools directory

re #23488

* small script changes and a couple of manual file changes

re #23488

* Minor chnage to whitespace detection in regex

re #23488

* Add an excluded directory

re #23488

* remove a repeasted copyright statement in a file

re #23488

* Don't comsume the comment end if it is on the same line

re #23488

* fix error in new copright parsing

re #23488

* remove double copyrifght entry

re #23488

* Improve handling of old copyrights at the start of comments

re #23488

* remove empty comments re #23488

* exclude gsoapgenerated directories

re #23488

* Sort out greedy line matching re #23488

* improve empty comment removal

re #23488

* improve false positives

re #23488

* impressive speedup by limiting regex matching length

re #23488

* remove evil invisible non ascii character

Also upadte the copyright at the same time

re #23488

* resolve multiple copyrights in a single file

re #23488

* resolve an issue with new statement detection

re #23488

* another unprintable unicode character

re #23488

* pep updates and cmake the new copyright fit clang format

re #23488

* update already done new format headers

re #23488

* wrong type of bracket

re #23488

* Update class_maker and friends

re #23488

* Update all copyright statements

re #23488

* clang format re #23488

* flake8 warnings re #23488

* Flake8 warnings re #23488

* Exclude .cmake.in and rb.in files

re #23488

* replace missing line re #23488

* exclude .py.in files as they are flasely recognized as C++

re #23488

* another setp.py.in re #23488

* another .py.in correction re #23488

* Hopefully the last of the .py.in files re #23488

* resolve utf-8 encoding of python files and changed ABINS checksum

re #23488

* updates to unit tests that reference line numbers

re #23488

* remaining unit test files and other fixes

re #23488

Update to clang-format-5 and reformat the codebase 

Primarily throwing exceptions rather than logging when there is an error.
This reports better to python, and prevents silent problems.
re #22918