Use RTE TextView for timeline text messages, add mention pills to messages (#1990)

* Add `formattedBody` to `TimelineItemTextBasedContent`.

This is pre-computed when timeline events are being mapped from the Rust SDK.

* Update `HtmlConverterProvider` styles.

* Improve `MentionSpan` to add missing `@` or `#` if needed

* Replace `HtmlDocument` with the `TextView` based component

* Improve extra padding calculation for timestamp by rounding the float offset result instead of truncating it.

* Remove composer line height workaround

* Use `ElementRichTextEditorStyle` instead of `RichTextEditorDefaults` for the theming

* Use slightly different styles for composer and messages (top/bottom line height discrepancies, mostly).

* Add `formattedBody` to notice and emote events.

---------

Co-authored-by: ElementBot <benoitm+elementbot@element.io>

features/messages/api/build.gradle.kts

@@ -15,7 +15,7 @@
  */
 
 plugins {
-    id("io.element.android-library")
+    id("io.element.android-compose-library")
 }
 
 android {

features/messages/api/src/main/kotlin/io/element/android/features/messages/api/timeline/HtmlConverterProvider.kt

@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2023 New Vector Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.element.android.features.messages.api.timeline
+
+import androidx.compose.runtime.Composable
+import io.element.android.libraries.matrix.api.core.UserId
+import io.element.android.wysiwyg.utils.HtmlConverter
+
+interface HtmlConverterProvider {
+
+    @Composable
+    fun Update(currentUserId: UserId)
+
+    fun provide(): HtmlConverter
+}