Add CSpline interpolation option to MonteCarloAbsoprtion

Avoid extra allocations in Strings::getLine.

Have cmake give location of mantid

Fix coverity warning in PDLoadCharacterizations

New algorithms `BinWidthAtX` and `MedianBinWidth`

Basic documentation for Levenberg-Marquardt MD Minimizer

Refs #18072 Update powder diffraction calibration concepts page.

Update mantidpython for python3

Add Start to visual-studio.bat to stop it staying open

Add small description of interpolation methods.

Refs #17801

Reflectometry (polref) documentation update

Dev rpm additions

Add PyYAML as runtime dependency

Rather than check for fedora, added flag for enabling python3

Conflicts:
	docs/source/release/v3.9.0/framework.rst
Refs #17801

Signed-off-by: Karl Palmen <karl.palmen@stfc.ac.uk>

Add "Save Workspaces" tab to Reflectometry (Polref) GUI

Get systemtests running with python3

This allows for people using `mantidpython`. This change
also removes the ability to set the location of mantid from
the command line.

Signed-off-by: Karl Palmen <karl.palmen@stfc.ac.uk>