Skip some checks for baseapps, extensions and console applications

[bbhtt]

This is a workaround until flatpak-builder-lint becomes fully flathub.json aware for builddir and repo checks

Baseapps and extensions should at minimum install a valid (passing appstream-util validate <file>) appdata file to be able to skip checks.

Eg baseapp with no appdata file https://github.com/flathub/org.mozilla.firefox.BaseApp will now error on:

# For baseapp

x flatpak-builder-lint builddir build
{
    "errors": [
        "appstream-missing-appinfo-file",
        "appstream-metainfo-missing"
    ]
}

→ flatpak-builder-lint repo repo 
/tmp/tmp40ksno6l
{
    "errors": [
        "appstream-missing-appinfo-file",
        "appstream-metainfo-missing",
        "appstream-missing-appinfo"
    ]
}

# For extension

→ flatpak-builder-lint builddir build                                            
{
    "errors": [
        "appstream-metainfo-missing",
        "appstream-missing-appinfo-file"
    ]
}

Don't need to check for extensions in check_repo because get_primary_refs returns refs starting with app/ only, but extensions start with runtime/

[bbhtt]

Added support for console applications too.

I don't see a way to not reach the appstream.is_console() check for icons for tests. Maybe there's some way to create the files on the fly using mock. I added some empty files to make them pass.

[bbhtt]

I don't see a way to not reach the appstream.is_console() check for icons for tests.

Figured out a way by moving it in check repo and check_build