[Docs] Add issue template (#113)

### What this PR does / why we need it?
Add issue templates.

Most of templates in this PR are from vllm-project/vllm:
https://github.com/vllm-project/vllm/tree/main/.github/ISSUE_TEMPLATE

### Does this PR introduce _any_ user-facing change?
No

### How was this patch tested?

Test on my local repo by setting default branch to ISSUE_TEMPLATE:
https://github.com/Yikun/vllm-ascend/issues

https://github.com/Yikun/vllm-ascend/issues/new/choose

Closes: https://github.com/vllm-project/vllm-ascend/issues/48

---------

Signed-off-by: Yikun Jiang <yikunkero@gmail.com>

.github/ISSUE_TEMPLATE/800-others.yml

@@ -0,0 +1,21 @@
+name: 🎲 Others
+description: Submit a discussion as you like. Note that developers are heavily overloaded and we mainly rely on community users to answer these issues.
+title: "[Misc]: "
+labels: ["misc"]
+
+body:
+- type: markdown
+  attributes:
+    value: >
+      #### Before submitting an issue, please make sure the issue hasn't been already addressed by searching through [the existing and past issues](https://github.com/vllm-project/vllm-ascend/issues?q=is%3Aissue+sort%3Acreated-desc+).
+- type: textarea
+  attributes:
+    label: Anything you want to discuss about vllm on ascend.
+    description: >
+      Anything you want to discuss about vllm on ascend.
+  validations:
+    required: true
+- type: markdown
+  attributes:
+    value: >
+      Thanks for contributing 🎉!