Replace java.time APIs with kotlin(x).(date)time (#3001)

* Replace java.time APIs with kotlin(x).(date)time

kotlinx-datetime explicitly says in its README that it does not cover
i18n, so we have to stick with using their toJavaX converters wherever
we localise dates and times.

Yes, some of these replacements are... questionable. But I wanted to
try and maximise the replacement for now.

* Bump kotlinx-datetime to 0.8.0

* More kotlin.time/kotlinx-datetime replacements

* Remove redundant init block & make attributes val

* Replace new use of java.time.Instant

data/src/main/java/tachiyomi/data/manga/MangaRepositoryImpl.kt

@@ -4,6 +4,9 @@ import app.cash.sqldelight.async.coroutines.awaitAsList
 import app.cash.sqldelight.async.coroutines.awaitAsOne
 import app.cash.sqldelight.async.coroutines.awaitAsOneOrNull
 import kotlinx.coroutines.flow.Flow
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.atStartOfDayIn
+import kotlinx.datetime.toLocalDateTime
 import logcat.LogPriority
 import tachiyomi.core.common.util.system.logcat
 import tachiyomi.data.Database
@@ -18,8 +21,7 @@ import tachiyomi.domain.manga.model.Manga
 import tachiyomi.domain.manga.model.MangaUpdate
 import tachiyomi.domain.manga.model.MangaWithChapterCount
 import tachiyomi.domain.manga.repository.MangaRepository
-import java.time.LocalDate
-import java.time.ZoneId
+import kotlin.time.Clock
 
 class MangaRepositoryImpl(
     private val database: Database,
@@ -86,7 +88,9 @@ class MangaRepositoryImpl(
     }
 
     override suspend fun getUpcomingManga(statuses: Set<Long>): Flow<List<Manga>> {
-        val epochMillis = LocalDate.now().atStartOfDay(ZoneId.systemDefault()).toEpochSecond() * 1000
+        val timeZone = TimeZone.currentSystemDefault()
+        val epochMillis =
+            Clock.System.now().toLocalDateTime(timeZone).date.atStartOfDayIn(timeZone).toEpochMilliseconds()
         return database.mangasQueries
             .getUpcomingManga(epochMillis, statuses, MangaMapper::mapManga)
             .subscribeToList()