Make test stat printing more coherent

[lgoettgens]

Resolves #4104.

For the markdown output, we can just log into the CI logs. For the PrettyTables output, someone would need to run tests locally.
@fingolfin is this what you wished for?

[benlorenz]

You don't need to run the full testsuite to test this, just make sure PrettyTables is available, paste the print_stats function to the repl and do:

julia> stats = Oscar.test_module("test/TropicalGeometry/", new=false,tempproject=false,timed=true)
...
julia> print_stats(stdout, stats; max=10)
### Stats per file

┌─────────────────────────────────────────┬──────────────┬───────────────┬─────────────────┬───────────────────┐
│                                Filename │ Runtime in s │ + Compilation │ + Recompilation │ Allocations in MB │
├─────────────────────────────────────────┼──────────────┼───────────────┼─────────────────┼───────────────────┤
│   test/TropicalGeometry/groebner_fan.jl │         7.66 │          2.34 │            0.00 │             426.2 │
│         test/TropicalGeometry/matrix.jl │         4.82 │          0.68 │            0.00 │              48.1 │
│   test/TropicalGeometry/linear_space.jl │         4.31 │          0.50 │            0.00 │              63.9 │
│        test/TropicalGeometry/variety.jl │         1.76 │          2.65 │            0.00 │             247.8 │
│   test/TropicalGeometry/intersection.jl │         1.09 │          5.07 │            0.00 │             393.5 │
│ test/TropicalGeometry/groebner_basis.jl │         0.03 │         12.92 │            0.00 │             915.6 │
│       test/TropicalGeometry/semiring.jl │         0.02 │          0.41 │            0.00 │              14.3 │
│        test/TropicalGeometry/initial.jl │         0.02 │          1.12 │            0.00 │              75.1 │
│   test/TropicalGeometry/semiring_map.jl │         0.02 │          0.46 │            0.00 │              14.3 │
│           test/TropicalGeometry/poly.jl │         0.02 │          0.40 │            0.00 │              18.7 │
└─────────────────────────────────────────┴──────────────┴───────────────┴─────────────────┴───────────────────┘

Seems to work fine (apart from the missing PrettyTables. prefix for the formatters).

[fingolfin]

Fantastic, thank you!