Fix navbar back button behavior (#195)

* Enable passing backLink through location state. Explicitly handle cases for BACK

* Allow pages to override default backLink. Fix manga page back link

* Cleanup

src/screens/Manga.tsx

@@ -10,7 +10,7 @@ import {
     CircularProgress, IconButton, Stack, Tooltip,
 } from '@mui/material';
 import { Box } from '@mui/system';
-import NavbarContext from 'components/context/NavbarContext';
+import NavbarContext, { useSetDefaultBackTo } from 'components/context/NavbarContext';
 import ChapterList from 'components/manga/ChapterList';
 import { useRefreshManga } from 'components/manga/hooks';
 import MangaDetails from 'components/manga/MangaDetails';
@@ -37,6 +37,8 @@ const Manga: React.FC = () => {
 
     const [refresh, { loading: refreshing }] = useRefreshManga(id);
 
+    useSetDefaultBackTo(manga?.inLibrary === false && manga.sourceId != null ? `/sources/${manga.sourceId}/popular` : '/library');
+
     useEffect(() => {
         // Automatically fetch manga from source if data is older then 24 hours
         // Automatic fetch is done only once, to prevent issues when server does