ICAT: Rewrite Catalog Loading

[Nick Draper]

The catalog loading in the ICAT interface is a mess and needs completely rewriting.

Existing code is split amoung MantidUI.cpp, IcatInvestigation and other algorithms and any that is no longer used needs to be cleared up.

It needs to:

• Handle the identification of the file is locally available automatically (disable the download button if the file is available locally, or in default save location)
• Download to the default save location rather than the temp location under mantidplot as this is not writable on linux.
• Handle the alteration of file paths for windows, linux and mac. ICAT could store one form and we will need to be able to convert to the others. This will likely need the default mount points to be set per facility, as well as the section that should be replaced. Mount points need to be overwritable in the user.properties file.
• hide the location section of the file list, a more usefull column would be to indicate if the file is available locally (in file search path or accessible via path.) We would need to make sure this does not affect performance too much.

[Martyn Gigg]

This is now effectively a dulicate of #7866.

[Stuart Campbell]

This ticket has been transferred to github issue ​8065