This adds some case normalization to both the scheme and the host. This was
previously messing up TreeUri content:// URLs like this:
content://com.android.externalstorage.documents/tree/1AFB-2402%3A/document/1AFB-2402%3Atesty.at.or.at%2Ffdroid%2Frepo
Turning them into:
content://com.android.externalstorage.documents/tree/1AFB-2402:/document/1AFB-2402:testy.at.or.at/fdroid/repo