feat: Timers

[pmatalon]

Description

Timers can be activated by the --timers argument.
Main samurai execution steps are timed, and the results are displayed at the end of the program, within the call to samurai::finalize().
Example:

                            Elapsed (s)    Fraction (%)
           ghost update           2.448            30.8
        mesh adaptation           2.419            30.4
    convection operator           1.956            24.6
            data saving           0.802            10.1
      field expressions           0.261             3.3
       ----------------
              (untimed)           0.061             0.8
       ------------------------------------------------
          total runtime           7.946           100.0

Changes in user code

• samurai now requires cli11.
• Although the new code is retrocompatible, the user codes that already use cli11 should get the app object from samurai::initialize():

auto& app = samurai::initialize("My app's description", argc, argv);

• CLI11_PARSE(app, argc, argv) should also be replaced with SAMURAI_PARSE(argc, argv).

Code of Conduct

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