Add "check" command

[hertg]

Add a check command that verifies the installation / configuration and prints useful information to troubleshoot and report issues.

Example

$ egpu-switcher check

general
-------
version:      0.19.0_20230304.133052_gh
configured:   true
enabled:      true

detection
---------
interval:     500ms
retries:      6

egpu
----
id:           1153611719250962689
model:        XFX Limited Speedster MERC 319 AMD Radeon RX 6900 XT Black
driver:       amdgpu
connected:    no

thunderbolt
-----------
security:     user
pre-boot:     yes

x.org
-----
file:         /etc/X11/xorg.conf.d/99-egpu-switcher.conf
present:      no