Stub issue templates by copying CKEditor 4 templates.

.github/ISSUE_TEMPLATE/1-bug-report.md

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+---
+name: "\U0001F41B Bug report"
+about: Report that something isn't working as expected.
+title: ''
+labels: type:bug
+assignees: ''
+
+---
+
+## 📝 Provide detailed reproduction steps (if any)
+
+1. …
+2. …
+3. …
+
+### ✔️ Expected result
+
+*What is the expected result of the above steps?*
+
+### ❌ Actual result
+
+*What is the actual result of the above steps?*
+
+## 📃 Other details
+
+* Browser: …
+* OS: …
+* CKEditor version: …
+* Installed CKEditor plugins: …
+
+---
+
+If you'd like to see this fixed sooner, add a 👍 reaction to this post.

.github/ISSUE_TEMPLATE/2-feature-request.md

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+---
+name: "⭐ Feature request"
+about: Propose something new.
+title: ''
+labels: type:feature
+assignees: ''
+
+---
+
+## 📝 Provide description of the new feature
+
+*What is the expected behavior of the proposed feature?*
+
+---
+
+If you'd like to see this feature implemented, add a 👍 reaction to this post.

.github/ISSUE_TEMPLATE/3-docs-issue.md

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+---
+name: "\U0001F4DA Docs issue"
+about: Report an issue related to documentation.
+title: ''
+labels: type:docs
+assignees: ''
+
+---
+
+## 📝 Provide a description of requested docs changes
+
+*What is the purpose and what should be changed?*

.github/ISSUE_TEMPLATE/4-security-issue.md

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+---
+name: "\U0001F6A8 Security issue"
+about: Report a security issue.
+title: ''
+labels: ''
+assignees: ''
+
+---
+
+⚠️ Please **DO NOT report security issues here**, use the contact form at https://ckeditor.com/contact/ instead. ⚠️

.github/ISSUE_TEMPLATE/5-task.md

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+---
+name: "\U0001F477 Task"
+about: It's neither a bug nor feature request.
+title: ''
+labels: type:task
+assignees: ''
+
+---
+
+## Provide description of the task
+
+*What steps should be taken to fulfil the task?*
+
+## 📃 Other details
+
+* Browser: …
+* OS: …
+* CKEditor version: …
+* Installed CKEditor plugins: …