[mesh] UX fixes:
* move mesh elements click->move->click instead press-> drag->release
* allow to select by drawing a polygon and select an existing polygon in the same map tool like for vector layer)
[feature] [mesh] allows the user to make geom transformation of mesh frame by changing the vertices coordinates by expression. Each coordinates (X,Y,Z) of selected vertices can be calculated with an expression allowing transformation of the mesh while the mesh is still valid.
Co-authored-by: Harrissou Sant-anna <delazj@gmail.com>