These paths may be used for bind mounts, which we can't accurately
discover. Leave a message in the logs accordingly, but allow these
paths.
fixes: #5185
Only build libfwupdplugin source files once; we were only using one
non-exported symbol and so move that to the exported map so we can just link
the library in the self tests.
We now have two plugins getting the ESP values, and we only allow hardcoding
the ESP in uefi_capsule.conf.
Make all this a lot simpler by moving the ESP+BDP code to `FuContext`, which
also means we can handle the override (via the config file) in the engine,
and the override (in the command line tools) using the same mechanism.
Also, automate the migration of the `OverrideESPMountPoint` -> `EspLocation`
when loading the engine.
Fixes https://github.com/fwupd/fwupd/issues/5042
Until gi-docgen is declared stable support either of them.
This effectively means that hand builds and CI builds will use
gi-docgen, but distro builds use gtk-doc-tools.
The end year is legally and functionally redundant, and more importantly causes
cherry-pick conflicts when trying to maintain old branches. Use git for history.
