Improved Github Issue templates (#1698)

.github/ISSUE_TEMPLATE/bug_report.md

 ---
 name: Bug report
-about: Create a report to help us improve. If you need help setting up your simulation
-  with Arbor, please start a new topic in Discussions.
+about: If Arbor crashes, produces incorrect output or does something unexpected, please create a report to help us improve.
 title: ''
 labels:
 - 'bug'
 assignees: ''
 
 ---
+<!-- Please add relevant labels to categorize your bug. -->
 
 **Describe the bug**
 <!-- A clear and concise description of what the bug is, steps to reproduce, expected behavior, etc. -->
 
-**Additional context**
+**Context**
 <!-- Add any other context about the problem here (e.g. OS, Arbor version, etc.). -->

.github/ISSUE_TEMPLATE/enhancement_proposal.md

 ---
 name: Arbor Enhancement Proposal
-about: 'An outline and rationale for a new feature or major change to Arbor. '
-title: 'AEP: [PROPOSAL]'
+about: An outline and rationale for a new feature or major change to Arbor. Use this label ONLY if you have formulated this and have some or a few ideas for its implementation.
+title: ''
 labels:
 - 'AEP'
 - 'enhancement'
 assignees: ''
 
 ---
+<!-- Please add relevant labels to categorize your AEP. -->
+
+## Goal
+
+
+## Rationale
+
+
+## Scope
+
+
+## Implementation

.github/ISSUE_TEMPLATE/feature_request.md

 ---
-name: Feature request
-about: 'Suggest an idea for Arbor. Add a clear and concise description of what the problem is and what you want to happen instead. '
+name: Feature Request
+about: Request a new feature that you need Arbor to have. Add a clear and concise description of what the feature addresses or solves and what you want to happen. The Arbor team will follow-up and help you flesh the feature out and help work towards an implementation.
 title: ''
 labels:
-- 'enhancement'
+- 'Feature Request'
 - 'help wanted'
+- 'enhancement'
+- 'neuroscience'
 assignees: ''
 
 ---
+<!-- Please add/remove relevant labels to categorize your feature. -->
+
+**Describe the feature you need**
+<!-- Example: I want Arbor to support file format X -->
+
+**Explain what it is supposed to enable**
+<!-- Example: Model database Y can export in format X, which means I could use their models in Arbor. -->
+
+**Additional context**
+<!-- Example: I'm writing a paper on the olfactory bulb and database Y has a model ready to go! -->