add A7 2017 support

* A5/A7 2017 are basically the same phone, so lets copy its config
* asserts taken from https://github.com/LineageOS/android_device_samsung_a7y17lte/blob/lineage-18.1/BoardConfig.mk#L28

README.md

@@ -62,7 +62,7 @@ Linux is currently the best supported platform (tested with Ubuntu 20.04/22.04 L
 
 ## Officially supported devices
 
-Currently, the **we support 73 devices** by various vendors and working on adding more soon!
+Currently, the **we support 74 devices** by various vendors and working on adding more soon!
 
 Support for these devices is provided as best effort, but things might still go wrong.
 Help to improve the tool by reporting any issues you might face.
@@ -77,6 +77,7 @@ Samsung | Galaxy A3 2017 | a3y17lte | SM-A320FL | tested
 Samsung | Galaxy A5 2016 | [a5xelte](https://wiki.lineageos.org/devices/a5xelte) | SM-A510F | tested
 Samsung | Galaxy A5 2017 | [a5y17lte](https://wiki.lineageos.org/devices/a5y17lte) | | tested
 Samsung | Galaxy A7 2016 | a7xelte | | tested
+Samsung | Galaxy A7 2017 | [a7y17lte](https://wiki.lineageos.org/devices/a7y17lte) | | untested
 Samsung | Galaxy Grand Prime VE | grandprimevelte | SM-G531F | tested
 Samsung | Galaxy S III Neo | s3ve3g | GT-I9301I | tested
 Samsung | Galaxy Tab S2 | [gts210vewifi](https://wiki.lineageos.org/devices/gts210vewifi/) | T813 | tested

openandroidinstaller/assets/configs/a7y17lte.yaml

@@ -0,0 +1,28 @@
+metadata:
+  maintainer: Tobias Sterbak (tsterbak)/SirRGB
+  device_name: Samsung Galaxy A7 (2017)
+  is_ab_device: false
+  device_code: a7y17lte
+  supported_device_codes:
+    - a7y17lte
+    - a7y17ltexx
+steps:
+  unlock_bootloader:
+  boot_recovery:
+    - type: call_button
+      content: >
+        As a first step, you need to boot into the bootloader. A bootloader is the piece of software,
+        that tells your phone how to start and run an operating system (like Android). Your device should be turned on.
+        Then press 'Confirm and run' to reboot into the bootloader. Continue once it's done.
+      command: adb_reboot_download
+    - type: call_button
+      content: >
+        In this step, you need to flash a custom recovery on your device.
+        Press 'Confirm and run' to start the process. Confirm afterwards to continue.
+      command: heimdall_flash_recovery
+    - type: confirm_button
+      img: samsung-buttons.png
+      content: >
+        Unplug the USB cable from your device. Then manually reboot into recovery by pressing the *Volume Down* + *Power buttons* for 8~10 seconds
+        until the screen turns black & release the buttons immediately when it does, then boot to recovery with the device powered off,
+        hold *Volume Up* + *Home* + *Power button*.