Add logging capabilities

[mhpob]

Probably best done using an unexported function that the others can access.

From --help:

 Logging options:
      --log [=PATH(=C:\Users\***\AppData\Local\Innovasea\VRPC\vdat)]
                                Enable file logging. Explicit path is
                                optional.
      --log-level LEVEL         Set filter threshold for file logging [0
                                (most verbose), 1000 (least verbose)]
      --trace                   Send all logging to console (no filtering)
      --trace-debug             Send logging to console with debug-level
                                filtering (200)
      --trace-info              Send logging to console with info-level
                                filtering (300)

Examples:

.\vdat.exe --trace
20240708 11:24:42.861 [D:LOG] Console log enabled
20240708 11:24:42.861 [I:LOG] App::execute_i(C:\Users\**\rvdat\vdat.exe --trace)

.\vdat.exe convert --format=csv.fathom "C:\\Users\\***/test_files/VR2AR_546310_20190613_1.vrl"  --log=.