Removed namespaces and un-used property.  Refs #8900.
Use namespaces directly as there are few. Refs #8900.
Remove unused `isValid` property. Refs #8900.

- Updated the wiki of each algorithm to better describe its purpose.
Removed unnecessary try/catches from catalog. Refs #8900.
Updated wiki of catalog algorithms. Refs #8900.
Update include guards to match class names. Refs #8900.
Merge remote-tracking branch 'origin/feature/8900_improve_icat_algorithms'