- Refactor: Extract new fn `binstalk::helpers::remote::does_url_exist`
- Use new quickinstall release schema in `binstalk::fetchers::QuickInstall`
- Optimize `fetchers::QuickInstall`: Generate url once in `Fetcher::new`
Avoid repeated string allocation plus `Url` parsing.
This also makes changing package_url and stats_url easier.
- Optimize `QuickInstall::report`: Use HEAD instead of GET
Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>