qt: Pre-0.18 split-off translations update

- Update transifex slug
- Mention update of MSVC build in `doc/translation_process.md`
- Do a `make translate` to update English translations
- Pull current translations from transifex

.tx/config

@@ -1,7 +1,7 @@
 [main]
 host = https://www.transifex.com
 
-[bitcoin.qt-translation-017x]
+[bitcoin.qt-translation-018x]
 file_filter = src/qt/locale/bitcoin_<lang>.ts
 source_file = src/qt/locale/bitcoin_en.ts
 source_lang = en