Provide a device instance builder that allows plugins to easily
create multiple instance IDs based on parent attributes.
Also fix a lot of the instance ID orders, so that we add more generic
IDs first, and more specific IDs after.
tristate features will automatically disable if dependencies marked
as required are missing.
Packagers can manually override using `auto_features`.
Link: https://mesonbuild.com/Build-options.html#features
We were calling g_module_symbol() 2703 times, which is actually more
expensive than you'd think.
It also means the plugins are actually what we tell people they are:
A set of vfuncs that get run. The reality before that they were dlsym'd
functions that get called at pretty random times.
There's no actual hardware to test this against yet, but this is how I
would lay out a plugin if there was.
We still need to work out a generic encapsulation for the offer and
payload (for each component and bank) so this can work with LVFS and
fwupd.
