sagemath: update to 10.8.

[dkwo]

There are some pain points left:

• run tests in parallel
• fix broken tests (some with maxima-ecl are reported in upstream sage)

@tornaria Can you comment if this looks the right direction to you?
They had some changes, deleted sagemath-standard.

[dkwo]

Also possibly relevant:

Message: Warning: The specified datadir does not contain the necessary Cremona database. Either specify a different datadir or specify a correct the correct path via the environment variable SAGE_SHARE during runtime.
../src/sage/meson.build:178: WARNING: The variable(s) 'FOURTITWO_CIRCUITS', 'FOURTITWO_GRAVER', 'FOURTITWO_GROEBNER', 'FOURTITWO_HILBERT', 'FOURTITWO_MARKOV', 'FOURTITWO_PPI', 'FOURTITWO_QSOLVE', 'FOURTITWO_RAYS', 'FOURTITWO_ZSOLVE', 'SAGE_MATHJAX_DIR', 'SAGE_ROOT', 'SAGE_VENV', 'configure_input' in the input file 'src/sage/config.py.in' are not present in the given configuration data.

as well as Build targets in project: 573 for ref.