clients/ivi-shell-user-interface.c: Add 'command' config

Previously, commands could only be specified by their path, so it was not possible to pass arguments.

Use the 'command' config first, and if it is NULL, fall back to the existing 'path' config.

add an example with "command=weston-simple-egl -v" like the following image,

I successfully tested by modifying 'test-ivi-shell-app', below is a part of the output.

*** Result ivi_application_exists/1: ok ok 1 ivi_application_exists/1 Received thread event mask 0x4 Test thread reaped. [19:34:59.518] no-op renderer SHM seed: 0 --- Fixture 1 () ok: passed 1, skipped 0, failed 0, total 1

Signed-off-by: Gyeyoung Baek gyeyoung976@gmail.com

Co-authored-by: Michael Olbrich m.olbrich@pengutronix.de