Update issue template to use discussions for questions (#6155)

* add issue config

* remove question template

* update URL

* Update README.md

* Update README.md

Co-authored-by: Rohit Gupta <rohitgr1998@gmail.com>

* Update .github/ISSUE_TEMPLATE/config.yml

Co-authored-by: Rohit Gupta <rohitgr1998@gmail.com>

Co-authored-by: Rohit Gupta <rohitgr1998@gmail.com>

Author: 2 people

.github/ISSUE_TEMPLATE/config.yml

@@ -0,0 +1,8 @@
+blank_issues_enabled: false
+contact_links:
+  - name: Ask a Question
+    url: https://github.com/PyTorchLightning/pytorch-lightning/discussions/new
+    about: Ask and answer Lightning related questions
+  - name: 💬 Slack
+    url: https://app.slack.com/client/TR9DVT48M/CQXV8BRH9/thread/CQXV8BRH9-1591382895.254600
+    about: Chat with our community

.github/ISSUE_TEMPLATE/how-to-question.md

@@ -391,10 +391,8 @@ Lightning is also part of the [PyTorch ecosystem](https://pytorch.org/ecosystem/
 ### Asking for help
 If you have any questions please:
 1. [Read the docs](https://pytorch-lightning.rtfd.io/en/latest).
-2. [Search through the Discussions](https://github.com/PyTorchLightning/pytorch-lightning/discussions).
-3. [Look it up in our forum (or add a new question)](https://forums.pytorchlightning.ai)
-4. [Join our slack](https://join.slack.com/t/pytorch-lightning/shared_invite/zt-f6bl2l0l-JYMK3tbAgAmGRrlNr00f1A).
-
+2. [Search through existing Discussions](https://github.com/PyTorchLightning/pytorch-lightning/discussions), or [add a new question](https://github.com/PyTorchLightning/pytorch-lightning/discussions/new)
+3. [Join our slack](https://join.slack.com/t/pytorch-lightning/shared_invite/zt-f6bl2l0l-JYMK3tbAgAmGRrlNr00f1A).
 ### Funding
 [We're venture funded](https://techcrunch.com/2020/10/08/grid-ai-raises-18-6m-series-a-to-help-ai-researchers-and-engineers-bring-their-models-to-production/) to make sure we can provide around the clock support, hire a full-time staff, attend conferences, and move faster through implementing features you request.