Update issue templates (#47)

* Redirect installation issues to Discourse

* Remove required reference to documentation on template issue

* Remove required reference to discussion on feature request template

* Fix automatic label on feature request template

* Replace plain issue template with free form developer template

Author: ricardoV94

.github/ISSUE_TEMPLATE/config.yml

@@ -2,4 +2,4 @@ blank_issues_enabled: false
 contact_links:
   - name: PyMC Discourse
     url: https://discourse.pymc.io/
-    about: Ask usage questions about PyMC or PyTensor
+    about: Ask installation usage questions about PyTensor

.github/ISSUE_TEMPLATE/developer.yml

@@ -0,0 +1,9 @@
+name: Developer issue
+description: This template is for developers only!
+
+body:
+- type: textarea
+  attributes:
+    label: Description
+  validations:
+    required: true

.github/ISSUE_TEMPLATE/documentation.yml

@@ -18,8 +18,6 @@ body:
       referring to. You can also check the development version of the
       documentation and see if this issue has already been addressed at
       https://pytensor.readthedocs.io/en/latest/.
-  validations:
-    required: true
 
 - type: textarea
   attributes:

.github/ISSUE_TEMPLATE/feature-request.yml

@@ -6,7 +6,7 @@
 name: Feature request
 description: Check instructions for submitting your idea on the mailing list first.
 title: "ENH: <Please write a comprehensive title after the 'ENH: ' prefix>"
-labels: [enhancements]
+labels: [feature request]
 
 
 body:
@@ -22,15 +22,6 @@ body:
       Check the [Contributor Guide](https://github.com/pymc-devs/pytensor/blob/main/CONTRIBUTING.md)
       if you need more information.
 
-- type: textarea
-  attributes:
-    label: "Link to a discussion"
-    description: >
-      Link to the discussion about this feature request in
-      [Discussions](https://github.com/pymc-devs/pytensor/discussions)
-  validations:
-    required: true
-
 - type: textarea
   attributes:
     label: "Before"