Paywalls: Markdown support (#1312)

This uses https://github.com/commonmark/commonmark-java for parsing, and
the rendering implementation is derived from
https://github.com/ErikHellman/MarkdownComposer/blob/master/app/src/main/java/se/hellsoft/markdowncomposer/MarkdownComposer.kt
with a lot changes to be able to use `Markdown()` in the same way we use
`Text()`, therefore being able to replace our usages everywhere.

<img width="352" alt="Screenshot 2023-10-05 at 12 27 37"
src="https://github.com/RevenueCat/purchases-android/assets/685609/08b05cf2-9c63-46bf-9f9f-b86f0225c34a">

gradle/libs.versions.toml

@@ -33,6 +33,7 @@ viewmodelCompose = "2.4.0"
 paparrazzi = "1.3.1"
 coil = "2.4.0"
 window = "1.1.0"
+commonmark = "0.21.0"
 
 [plugins]
 android-application = { id = "com.android.application", version.ref = "agp" }
@@ -120,6 +121,9 @@ window-core = { module = "androidx.window:window-core", version.ref = "window" }
 coil-compose = { module = "io.coil-kt:coil-compose", version.ref = "coil" }
 coil-svg = { module = "io.coil-kt:coil-svg", version.ref = "coil" }
 
+commonmark = { module = "org.commonmark:commonmark", version.ref = "commonmark" }
+commonmark-strikethrough = { module = "org.commonmark:commonmark-ext-gfm-strikethrough", version.ref = "commonmark" }
+
 navigation-compose = "androidx.navigation:navigation-compose:2.5.3"
 
 [bundles]

ui/revenuecatui/build.gradle

@@ -53,6 +53,8 @@ dependencies {
     implementation libs.androidx.lifecycle.viewmodel.compose
     implementation libs.coil.compose
     implementation libs.coil.svg
+    implementation libs.commonmark
+    implementation libs.commonmark.strikethrough
     debugImplementation libs.compose.ui.tooling
     debugImplementation libs.androidx.test.compose.manifest
 

ui/revenuecatui/src/main/kotlin/com/revenuecat/purchases/ui/revenuecatui/composables/IntroEligibilityStateView.kt

@@ -1,6 +1,5 @@
 package com.revenuecat.purchases.ui.revenuecatui.composables
 
-import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.text.TextStyle
@@ -30,7 +29,7 @@ internal fun IntroEligibilityStateView(
         textWithNoIntroOffer ?: textWithIntroOffer ?: ""
     }
 
-    Text(
+    Markdown(
         text,
         color = color,
         style = style,