j4status-plugin: Split plugin interface struct

Signed-off-by: Quentin Glidic <sardemff7+git@sardemff7.net>
j4status: Split plugin logic to libj4status-plugin

Plugin must now link to libeventd-plugin
This allows ABI compatibility checks using shared library
mechanisms

Signed-off-by: Quentin Glidic <sardemff7+git@sardemff7.net>
Update copyright notices

Signed-off-by: Quentin Glidic <sardemff7+git@sardemff7.net>
nm: Remove leftovers

We already update the device status when monitoring (so when starting)
Reversing the list is useless since we already sorted our sections
anyway

Signed-off-by: Quentin Glidic <sardemff7+git@sardemff7.net>
nm: Use temp vars to set section name and label

It will make cleaner coming changes

Signed-off-by: Quentin Glidic <sardemff7+git@sardemff7.net>
nm: Do not add a section for unknown hardware

Signed-off-by: Quentin Glidic <sardemff7+git@sardemff7.net>
j4status-plugin: Hide section internals

This will make the ABI more stable in the future

Signed-off-by: Quentin Glidic <sardemff7+git@sardemff7.net>
sensors: Pre-acquire subfeatures

Signed-off-by: Quentin Glidic <sardemff7+git@sardemff7.net>