Fix selection of Portuguese translation files.

Qt returns "Brazil" as country of QLocale("pt") instead of "Portugal". This conflicts with QLocale("pt_BR").
Rename the pt.ts to pt_PT and put a language mapping in tx's config for that locale.
Closes #4776.

.tx/config

@@ -3,6 +3,7 @@ host = https://www.transifex.com
 
 [qbittorrent.qbittorrent_master]
 file_filter = src/lang/qbittorrent_<lang>.ts
+lang_map = pt: pt_PT
 source_file = src/lang/qbittorrent_en.ts
 source_lang = en
 type = QT

src/lang.qrc

@@ -31,7 +31,7 @@
   <file>lang/qbittorrent_nb.qm</file>
   <file>lang/qbittorrent_nl.qm</file>
   <file>lang/qbittorrent_pl.qm</file>
-  <file>lang/qbittorrent_pt.qm</file>
+  <file>lang/qbittorrent_pt_PT.qm</file>
   <file>lang/qbittorrent_pt_BR.qm</file>
   <file>lang/qbittorrent_ro.qm</file>
   <file>lang/qbittorrent_ru.qm</file>

src/src.pro

@@ -98,7 +98,7 @@ TRANSLATIONS = \
     $$LANG_PATH/qbittorrent_sk.ts \
     $$LANG_PATH/qbittorrent_sl.ts \
     $$LANG_PATH/qbittorrent_ro.ts \
-    $$LANG_PATH/qbittorrent_pt.ts \
+    $$LANG_PATH/qbittorrent_pt_PT.ts \
     $$LANG_PATH/qbittorrent_nb.ts \
     $$LANG_PATH/qbittorrent_fi.ts \
     $$LANG_PATH/qbittorrent_da.ts \