Add docs for Fire TV (virtual) integration (#25716)

source/_integrations/fire_tv.markdown

@@ -0,0 +1,21 @@
+---
+title: Amazon Fire TV
+description: Instructions on how to integrate Amazon Fire TV devices into Home Assistant.
+ha_category:
+  - Media Player
+ha_domain: fire_tv
+ha_integration_type: virtual
+ha_supporting_domain: androidtv
+ha_supporting_integration: Android TV
+ha_release: 0.7.6
+ha_codeowners:
+  - '@JeffLIrion'
+  - '@ollo69'
+ha_config_flow: true
+ha_platforms:
+  - diagnostics
+  - media_player
+ha_iot_class: Local Polling
+---
+
+{% include integrations/supported_brand.md %}