Moving download sources into its own module

Author: Hainish

src/apkpure.rs src/download_sources/apkpure.rssrc/apkpure.rs renamed to src/download_sources/apkpure.rs

@@ -0,0 +1,4 @@
+pub mod google_play;
+pub mod fdroid;
+pub mod apkpure;
+pub mod huawei_app_gallery;

src/fdroid.rs src/download_sources/fdroid.rssrc/fdroid.rs renamed to src/download_sources/fdroid.rs

@@ -136,10 +136,11 @@ mod config;
 mod consts;
 mod util;
 
-mod apkpure;
-mod fdroid;
-mod google_play;
-mod huawei_app_gallery;
+mod download_sources;
+use download_sources::google_play;
+use download_sources::fdroid;
+use download_sources::apkpure;
+use download_sources::huawei_app_gallery;
 
 type CSVList = Vec<(String, Option<String>)>;
 fn fetch_csv_list(csv: &str, field: usize, version_field: Option<usize>) -> Result<CSVList, Box<dyn Error>> {