feat(dialog): add xdg-portal as an optional feature for rfd

[Lepidopteran]

Adds a feature to be able to use xdg-portal instead of gtk3 for tauri-plugin-dialog
Let me know if any changes are needed!

Continues #2376

[FabianLars]

that was quick, thanks! For the plugin i don't think there's much more to do except for a small changefile and maybeee some docs that relay some of rfd's xdg info.
The major thing is the zenity dependency but that's something to worry about in the tauri repo x)

[FabianLars]

oh and ci may fail because we set --all-features

[github-actions]

Package Changes Through 0e6a509

There are 12 changes which include dialog-js with minor, dialog with minor, log with minor, log-js with minor, barcode-scanner with patch, barcode-scanner-js with patch, nfc with patch, nfc-js with patch, updater with minor, updater-js with minor, upload with minor, upload-js with minor

Planned Package Versions

The following package releases are the planned based on the context of changes in this pull request.

package	current	next
api-example	2.0.38	2.0.39
api-example-js	2.0.34	2.0.35
barcode-scanner	2.4.2	2.4.3
barcode-scanner-js	2.4.2	2.4.3
dialog	2.4.2	2.5.0
dialog-js	2.4.2	2.5.0
log	2.7.1	2.8.0
log-js	2.7.1	2.8.0
nfc	2.3.3	2.3.4
nfc-js	2.3.3	2.3.4
updater	2.9.0	2.10.0
updater-js	2.9.0	2.10.0
upload	2.3.2	2.4.0
upload-js	2.3.2	2.4.0

Add another change file through the GitHub UI by following this link.

---

Read about change files or the docs at github.com/jbolda/covector

[Lepidopteran]

maybeee some docs that relay some of rfd's xdg info.

I can do that, by docs are you referring to README.md in the dialog plugin folder or is it something else?

[Lepidopteran]

If you don't mind me asking, Is there anything else I need to do @FabianLars?

I've added the changefile to .changes like you requested, but I'm not sure where to write the documentation about rfd's xdg info.

Should I be writing it in dialog-plugin's README.md?

Additionally, when relaying some of the rfd's docs, am I explaining that zenity and an XDG portal needs to be installed on the users machine?

[FabianLars]

I didn't have time for your pr yet (cause I wanted to try it but we can discard this)
We can leave it as is or ideally add just a few lines to the readme. Mentioning zenity and the portal would be nice. Anything more extensive should be on the website.

[Lepidopteran]

I added a section about XDG desktop support to the README, lemme know if any changes need to be made!

[FabianLars]

thanks!

[FabianLars]

good thing i waited for CI - mutually exclusive features need special handling there (see http) - it's too late for me now so if we can't figure it out i'll do it tomorrow :)