Started to add SolidMechanicsModelCLIP class

Functionnality which are already implemented:

• Creation of CLIP mesh in SolidMechanicsModelCLIP::createCLIPMesh(). Requires to download and compile gmsh from source
• Precomputation of CLIP shape functions at computation mesh integration points in computeShapeFunctionsOnIntegrationPoints() function
• Started to add computeBulkDamage to SolidMechanicsModelCLIP : for now it can read and write czm_damage from MaterialCohesiveDamage (see readDamage and writeDamage functions). Interpolation of bulk damage at computation mesh integration points from clip mesh nodal values is done in interpolateBulkDamageOnIntegrationPoints(), but it lacks the FEEngineTemplate::contains function to work (for now it looks like this function does not compile)
• Added a SolidMechanicsModelCLIP::initializeCZMDamage function to initiaze cohesive damage. Can be used to do some tests.
• Export of clip_czm_damage and bulk_czm_damage has been added
• Added a clip_compute_damage test case to test SolidMechanicsModelCLIP functionnalities
  
  TODO:
• Fixed FEEngineTemplate::contains to check that interpolateBulkDamageOnIntegrationPoints() and computeShapeFunctionsOnIntegrationPoints() work
• Maybe merge MaterialCohesiveDamageExtrinsic and MaterialCohesiveDamageIntrinsic (or just remove MaterialCohesiveDamageExtrinsic)