uclient: provide virtual wget-any

uclient: provide virtual wget-any

Packages shouldn't provide a package that another package, in this case
wget from packages provides. Explicitly provide a virtual @wget-any
instead to match the implicit wget provide and switch the only consumer
to use the new provider.

Set uclient-fetch as the default variant for wget-any.

Signed-off-by: George Sapkin <george@sapk.in>
Link: https://github.com/openwrt/openwrt/pull/21369
(cherry picked from commit af1fa176c31368e5e56c5a1f31d8a12273536378)
Link: https://github.com/openwrt/openwrt/pull/21547
Signed-off-by: Robert Marko <robimarko@gmail.com>