v0.7.10

Trixi v0.7.10

Diff since v0.7.9

Merged pull requests:

• GLM speed calculations for coupled semidiscretizations (#1835) (@SimonCan)
• Fix intern time integration method with fixed time step (#1919) (@bennibolm)
• Remove unused variables save_time_series_file (#1928) (@DanielDoehring)