[#1496] Image conversion (#1505)

* [#1496] First conversion attempt

* [#1496] Configurable conversion

* Fix: allow nested configs (map)

* [#1496] Support explicit `none` conversion

* Use MimeUtils for provided download

* [1496] Support image conversion on load for downloaded images

* Lint

* [#1496] Support conversion on fresh download as well

Previous commit was only for already downloaded images, now also for
fresh and cached

* [#1496] Refactor: Move where conversion for download happens

* Rewrite config handling, improve custom types

* Lint

* Add format to pages mutation

* Lint

* Standardize url encode

* Lint

* Config: Allow additional conversion parameters

* Implement conversion quality parameter

* Lint

* Implement a conversion util to allow fallback readers

* Add downloadConversions to api and backup, fix updateValue issues

* Lint

* Minor cleanup

* Update libs.versions.toml

---------

Co-authored-by: Syer10 <syer10@users.noreply.github.com>

server/src/test/resources/server-reference.conf

@@ -26,6 +26,12 @@ server.autoDownloadNewChapters = false # if new chapters that have been retrieve
 server.excludeEntryWithUnreadChapters = true # ignore automatic chapter downloads of entries with unread chapters
 server.autoDownloadNewChaptersLimit = 0 # 0 to disable it - how many unread downloaded chapters should be available - if the limit is reached, new chapters won't be downloaded automatically. this limit will also be applied to the auto download of new chapters on an update
 server.autoDownloadIgnoreReUploads = false # decides if re-uploads should be ignored during auto download of new chapters
+server.downloadConversions = {}
+# map input mime type to conversion information, or "default" for others
+# server.downloadConversions."image/webp" = {
+#   target = "image/jpeg"   # image type to convert to
+#   compressionLevel = 0.8  # quality in range [0,1], leave away to use default compression
+# }
 
 # extension repos
 server.extensionRepos = [