Rename AddTopLayer to AddLayer

See merge request ogs/ogs!3015

New and better error messages for test definitions

See merge request ogs/ogs!3021

[CL] Chemical calculation shifted from nodes to int_pts (Part I): Extrapolate post reaction solution to nodes

See merge request ogs/ogs!3017

Abort if test definitions exist but no tests were actually
constructed from the configuration.

This can happen if the regex does not match any of the files
in the reference solutions directory.

The argument characterizes the direction the layer is added - either on top or on bottom.

Use directly addLayerToMesh.

[App] Add log level setting to partmesh.

See merge request ogs/ogs!3012

[PL/Output] Escape {} to fix bug in error message.

See merge request ogs/ogs!3013

Change of OGS version only affects frontpage and navigation tree.
The navigation tree is a single html embedded into every page.
This helps in better CDN caching and faster uploads on Netlify.