Fix performance issue with IterativeFull solver.

Removes the request for Robin BC info every iteration of the CG solver.

See merge request !693

Fix issue with output in parallel

This fixes an issue some people have experienced where only part of the files in an fld are written in parallel.

See merge request !699

Feature/insert new logic

Adds non-conforming logic to the high-order surface insert routine to get it to work with symmetry planes from star-ccm+ meshes.
It also clears up a couple of bugs which were introduced in previous merges because buildbot didnt test NEKTAR_USE_MESHGEN, also fixes the associated tests.

See merge request !700

scaled jacobian option to qualitymetric module

as titled.
Picked from meshgeneration/feature/varopti_DNC

See merge request !695

Feature/nekmesh-check-links

Clears the existing element links in the mesh and reprocesses them. It then checks that all faces are linked to two elements or to one element and a boundary face.
Designed to be used with the bl split module to detect errors and user mistakes (creating hanging faces etc). Its been made into its own module so it can be used anywhere.

See merge request !691

feature/qualitythreshold_linearise

add quality threshold to linearise module so that any elements below a certain value will linearised. This works based on the scaled jacobian.

See merge request !690

cadcurve projection

small addition to allow points to be projected onto cad curves.

See merge request !697

Rework nodal utilities and add support for nodal prisms

This MR refactors the nodal points utilities that are found in the `NodalUtil.h` and `NodalUtil.cpp` files, and introduces a new `NodalUtil` class which handles the generation of Vandermonde matrices, integration weights, interpolation matrices and derivative matrices for arbitrary sets of points on the triangle, tetrahedron and prism elements. The latter element is newly supported.

This branch:
- Significantly reduces the amount of code from sporadic function calls to a more organised class structure, eliminating most duplicate code
- Fixes a bug in the generation of nodal tetrahedral weights
- Enables the use of nodal prism elements
- Adds a lot of doxygen documentation to describe the new structure
- Replaces the NodalUtil demos with a single NodalDemo, which is now tested in the regression tests

This should be seen as a stepping-stone branch, depending on the outcome of the working being done in the feature/basis-refactor branch, but will hopefully make any further efforts easier.

See merge request !660

feature/cadsystem_factories

This merge takes the existing OCE cad engine and turns it into a more general system where OCE is the default backend.
This is in preparation of CFI and other installation dependant backends being added.
All tests pass (these are not on buildbot yet).

See merge request !676

feature/prisms only linearise

In an effort to reduce cost on massive meshes, this makes the linearise module only consider prisms (which is most cases are the only deformed elements

See merge request !688