[Feat] Enable selective test to be run in docker or cloud deployment

[neteler]

At time is is difficult to understand if a GRASS GIS installation is functional or not when performing automated installations/deployments (e.g. docker based).

While there is gunittest it is still hard to enable (selected) tests in

• dockerfiles (building images with GRASS GIS included),
• CI systems
• HPC deployments (install and run on worker nodes),
• kubernetes, OpenStack etc (deploy images)

A mechanism is desired which executes individual tests, by ideally having either a representative ("some tests in each module family") or a topical coverage ("test only the libraries and some vector analysis").

Describe the solution you'd like

Be able to run a set of tests by invoking make test. Or, more selectively

• make minitest
• make largetest

The tests should be based on different datasets, i.e.

• larger tests: on a well defined dataset, e.g. North Carolina sample dataset
• small unit tests: self-contained tests with synthetic data.

While writing the missing tests is a separated topic, we need a mechanism in the first place.

Describe alternatives you've considered
Former attempt here: #342