Fix appdata related issues

[yakushabb]

• Add missing developer block
• Update homepage to github page, due to the wiki page are going to be retired.
• Add vcs-browser URL
• Update translation URL
• Remove the none aors rules
• Fix the updatecontact tag
• Copy screenshots to the repository

[diegogangl]

Thanks for working on this! Everything looks good. One thing we should discuss is how often we expect screenshots to change. If they don't, then it makes some sense to have them in the repo, otherwise I would keep them in a server/wiki to avoid ballooning the repo with binary data.

What do you think @nekohayo ?

[yakushabb]

GNOME wiki pages are going to be retired.

Old screenshots links seem not working.

[diegogangl]

Yes, but we could put them in this repo's wiki:
https://github.blog/changelog/2022-02-14-upload-images-to-wiki-pages/

[yakushabb]

If you kindly provide URLs, I can update them. It seems that 'gtg' does not have a wiki page on GitHub.

[diegogangl]

While trying it, it seems we can't control the urls of the images we post. I wonder if @nekohayo would mind hosting the images? Otherwise we can put them in git lfs

[Neui]

You can clone a git wiki repo on the wiki page, does commiting images there and pushing them work?

[yakushabb]

I really have no idea how to commit a wiki page on GitHub.

I suppose providing an image URL should work for AppData.

[diegogangl]

Thanks for tip @Neui !
@yakushabb Sorry for the wait, here are the urls:

https://raw.githubusercontent.com/wiki/getting-things-gnome/gtg/assets/screenshots/0.6/main_with_background.png
https://raw.githubusercontent.com/wiki/getting-things-gnome/gtg/assets/screenshots/0.6/main_window.png
https://raw.githubusercontent.com/wiki/getting-things-gnome/gtg/assets/screenshots/0.6/detail.png

[yakushabb]

Updated.

[diegogangl]

...and merged!
Thanks for the work :)