separated web and api, build improvements

wip:
- separate web and api servers.
- script for building static pages.
- building improvements.
- async localisation preloading.

src/localization/languages/en.json

@@ -47,7 +47,7 @@
         "SettingsQualityDescription": "if selected quality isn't available, closest one is used instead.",
         "LinkGitHubChanges": ">> see previous commits and contribute on github",
         "NoScriptMessage": "{appName} uses javascript for api requests and interactive interface. you have to allow javascript to use this site. there are no pesty scripts, pinky promise.",
-        "DownloadPopupDescriptionIOS": "easiest way to save videos on ios:\n1. add <a class=\"text-backdrop italic\" href=\"{saveToGalleryShortcut}\" target=\"_blank\">this siri shortcut</a>.\n2. press \"share\" above and select \"save to photos\" in appeared share sheet.\nif asked, review the permission request popup on top, and press \"always allow\".\n\nalternative method: press and hold the download button, hide the video preview, and select \"download linked file\" to download.\nthen, open safari downloads, select the file you downloaded, open share menu, and finally press \"save video\".",
+        "DownloadPopupDescriptionIOS": "easiest way to save videos on ios:\n1. add <a class=\"text-backdrop italic\" href=\"{saveToGalleryShortcut}\" target=\"_blank\">this siri shortcut</a>.\n2. press \"share\" above and select \"save to photos\" in appeared share sheet.\nif asked, review the permission request, and press \"always allow\".\n\nalternative method:\npress and hold the download button, hide the video preview, and select \"download linked file\" to download.\nthen, open safari downloads, select the file you downloaded, open share menu, and finally press \"save video\".",
         "DownloadPopupDescription": "download button opens a new tab with requested file. you can disable this popup in settings.",
         "DownloadPopupWayToSave": "pick a way to save",
         "ClickToCopy": "press to copy",