[FEATURE] Introduces memory dataset groups for mesh layer. These dataset groups are temporary and are not kept when the project is closed.
Memory dataset groups can be created from the mesh calculator with a new option.
Allows the possibility to remove or save these memory dataset groups to a file with specified driver.
* MDAL 0.5.90 : support for custom Logger and 1D meshes
* [FEATURE] [MESH] Support rendering of 1D meshes, see https://github.com/qgis/QGIS-Enhancement-Proposals/issues/164
1D mesh consist of edges (edge is straight line segment with 2 vertices) and the data that is defined on either
vertices or edges. Such data can be loaded by MDAL and rendered as mesh layer in QGIS.
