Dunfell support

[jatedev]

While dunfell is going end of life, it might be useful to have plugin compatible for those who are still on it if it's not too much effort.

Import "oe.data" could not be resolved
Import "oe.path" could not be resolved
Import "bb.compress.zstd" could not be resolved`
Import "oe.utils" could not be resolved
Import "oe.types" could not be resolved
Import "oe.package" could not be resolved
Import "oe.packagegroup" could not be resolved
Import "oe.sstatesig" could not be resolved
Import "oe.lsb" could not be resolved
Import "oe.cachedpath" could not be resolved
Import "oe.license" could not be resolved
Import "oe.qa" could not be resolved
Import "oe.reproducible" could not be resolved
Import "oe.rust" could not be resolved
Import "oe.buildcfg" could not be resolved`

[deribaucourt]

As you said, since dunfell is EOL, we do not plan to add backwards compatibility with it. Any contribution that would make the extension more compatible with previous releases while not adding regressions for the current releases would be welcome though :)

[jatedev]

@deribaucourt : I was able to configure the plugin and the definition peeking and parsing are working with dunfell. For that, they only appear to be warnings.

Are the imports for devtool, recipe building, and the other functionality in VS Code?