Add Issue Templates (#1456)

* Add Issue Templates

This disable the creation of empty issues and adds some templates when one is opened.
A link to our discord is directly added to the issue templates list.

Thanks EmulationFanatic for the proof reading.

* fix copy paste

* Fix name

.github/ISSUE_TEMPLATE/missing_cpu_instruction.md

@@ -0,0 +1,34 @@
+---
+name: Missing CPU Instruction
+about: CPU Instruction is missing in Ryujinx.
+#assignees:
+---
+
+## Missing CPU Instruction
+
+[ If any section does not apply, replace its contents with "N/A". ]</br>
+[ If you do not have the information needed for a section, replace its contents with "Unknown". ]</br>
+[ Lines between [ ] (square brackets) are to be removed before posting. ]
+
+[ Please search for existing [missing CPU instruction](https://github.com/Ryujinx/Ryujinx/issues) before you make your own issue. ]</br>
+[ See the following [issue](https://github.com/Ryujinx/Ryujinx/issues/1405) as an example ]</br>
+[ Duplicate issue will be marked as such and you will be referred to the original request. ]
+
+### What CPU instruction is missing?
+
+Requires the *INSTRUCTION* instruction.</br>
+[ Replace *INSTRUCTION* by the instruction name, e.g. VADDL.U16 ]
+
+```
+*
+```
+[ Add the undefined instruction error message in the above code block ]
+
+### Instruction name
+```
+*
+```
+[ Include the name from [armconverter.com](https://armconverter.com/?disasm) or [shell-storm.org](http://shell-storm.org/online/Online-Assembler-and-Disassembler/?arch=arm64&endianness=big&dis_with_raw=True&dis_with_ins=True) in the above code block ]
+
+### Required by: 
+[ Add our (games list database)[https://github.com/Ryujinx/Ryujinx-Games-List/issues] links of games who require this instruction ]