[Feature Request] - support local rss file

[Cyrix126]

Description

tuifeed doesn't support local atom/rss file. It will try to download it with a http client.

Changes

Adding a local rss file in the config like this is validated in the config
local-rss = "file:///your_path/file.rss"
But throw an error when opening tuifeed

Could not fetch feed "local-rss": HTTP request failed: Bad URL: failed to parse
 URL: EmptyHost: empty host