refac: i18n (#244)

frontend/src/views/Filebrowser.tsx

@@ -216,7 +216,7 @@ export default function Downloaded() {
         onClick={() => setShowMenu(false)}
       >
         <List sx={{ width: '100%', bgcolor: 'background.paper' }}>
-          {selectable.length === 0 && 'No files found'}
+          {selectable.length === 0 && i18n.t('noFilesFound')}
           {selectable.map((file, idx) => (
             <ListItem
               onContextMenu={(e) => {
@@ -275,7 +275,7 @@ export default function Downloaded() {
       >
         <SpeedDialAction
           icon={<DeleteForeverIcon />}
-          tooltipTitle={`Delete selected`}
+          tooltipTitle={i18n.t('deleteSelected')}
           tooltipOpen
           onClick={() => {
             if (selected$.value.length > 0) {

frontend/src/views/Settings.tsx

@@ -284,8 +284,8 @@ export default function Settings() {
                 label={i18n.t('themeSelect')}
                 onChange={handleThemeChange}
               >
-                <MenuItem value="light">Light</MenuItem>
-                <MenuItem value="dark">Dark</MenuItem>
+                <MenuItem value="light">{i18n.t('lightThemeButton')}</MenuItem>
+                <MenuItem value="dark">{i18n.t('darkThemeButton')}</MenuItem>
                 <MenuItem value="system">System</MenuItem>
               </Select>
             </FormControl>
@@ -308,7 +308,7 @@ export default function Settings() {
           </Grid>
         </Grid>
         <Typography variant="h6" color="primary" sx={{ mt: 2, mb: 0.5 }}>
-          General download settings
+          {i18n.t('generalDownloadSettings')}
         </Typography>
 
         <FormControlLabel