remove instamanhwa (#4528)

src/en/instamanhwa/build.gradle

@@ -1,10 +0,0 @@
-ext {
-    extName = 'InstaManhwa'
-    extClass = '.InstaManhwa'
-    themePkg = 'madara'
-    baseUrl = 'https://www.instamanhwa.com'
-    overrideVersionCode = 2
-    isNsfw = true
-}
-
-apply from: "$rootDir/common.gradle"

src/en/instamanhwa/src/eu/kanade/tachiyomi/extension/en/instamanhwa/InstaManhwa.kt

@@ -1,12 +0,0 @@
-package eu.kanade.tachiyomi.extension.en.instamanhwa
-
-import eu.kanade.tachiyomi.multisrc.madara.Madara
-
-class InstaManhwa : Madara(
-    "InstaManhwa",
-    "https://www.instamanhwa.com",
-    "en",
-) {
-    override val filterNonMangaItems = false
-    override val useNewChapterEndpoint = true
-}