feat: hostmetaのエンドポイントを追加

src/main/kotlin/dev/usbharu/hideout/controller/wellknown/HostMetaController.kt

@@ -0,0 +1,42 @@
+package dev.usbharu.hideout.controller.wellknown
+
+import dev.usbharu.hideout.config.ApplicationConfig
+import org.intellij.lang.annotations.Language
+import org.springframework.http.HttpStatus
+import org.springframework.http.ResponseEntity
+import org.springframework.web.bind.annotation.GetMapping
+import org.springframework.web.bind.annotation.RestController
+
+@RestController
+class HostMetaController(private val applicationConfig: ApplicationConfig) {
+
+    val xml = //language=XML
+        """<?xml version="1.0" encoding="UTF-8"?>
+<XRD xmlns="http://docs.oasis-open.org/ns/xri/xrd-1.0">
+    <Link rel="lrdd" type="application/xrd+xml"
+          template="${applicationConfig.url}/.well-known/webfinger?resource={uri}"/>
+</XRD>"""
+
+    @Language("JSON")
+    val json = """{
+  "links": [
+    {
+      "rel": "lrdd",
+      "type": "application/jrd+json",
+      "template": "${applicationConfig.url}/.well-known/webfinger?resource={uri}"
+    }
+  ]
+}"""
+
+    @GetMapping("/.well-known/host-meta", produces = ["application/xml"])
+    fun hostmeta(): ResponseEntity<String> {
+        return ResponseEntity(xml, HttpStatus.OK)
+    }
+
+    @GetMapping("/.well-known/host-meta.json", produces = ["application/json"])
+    fun hostmetJson(): ResponseEntity<String> {
+        return ResponseEntity(json, HttpStatus.OK)
+    }
+
+
+}