*: Change GitHub issue template to use the forum (#40779)

.github/ISSUE_TEMPLATE/config.yml

@@ -0,0 +1,8 @@
+blank_issues_enabled: false
+contact_links:
+  - name: TiDB Forum
+    url: https://ask.pingcap.com/
+    about: Ask a question on the TiDB Forum
+  - name: TiDB Forum(Chinese)
+    url: https://asktug.com/
+    about: Ask a question on the TiDB user group (Chinese)

.github/ISSUE_TEMPLATE/general-question.md

@@ -1,20 +0,0 @@
----
-name: "\U0001F914 Ask a Question"
-about: I want to ask a question.
-labels: type/question
----
-
-## General Question
-
-<!--
-
-Before asking a question, make sure you have:
-
-- Searched existing Stack Overflow questions.
-- Googled your question.
-- Searched open and closed [GitHub issues](https://github.com/pingcap/tidb/issues?utf8=%E2%9C%93&q=is%3Aissue)
-- Read the documentation:
-  - [TiDB Readme](https://github.com/pingcap/tidb)
-  - [TiDB Doc](https://github.com/pingcap/docs)
-
--->

.github/ISSUE_TEMPLATE/performance-questions.md

@@ -1,29 +0,0 @@
----
-name: "\U0001F947 Ask a Database Performance Question"
-about: I want to ask a database performance question.
-labels: type/question, type/performance
----
-
-## Performance Questions
-
-- What version of TiDB are you using?
-<!-- You can try `tidb-server -V` or run `select tidb_version();` on TiDB to get this information -->
-
-- What's the observed and your expected performance respectively?
-
-- Have you compared TiDB with other databases? If yes, what's their difference?
-
-- For a specific slow SQL query, please provide the following information:
-    - Whether you analyzed the tables involved in the query and how long it is after you ran the last `ANALYZE`.
-    - Whether this SQL query always or occasionally runs slowly.
-    - The `EXPLAIN ANALYZE` result of this query if your TiDB version is higher than 2.1, or you can just provide the `EXPLAIN` result.
-    - The plain text of the SQL query and table schema so we can test it locally. It would be better if you can provide the dumped statistics information.
-        <!-- you can use `show create table ${involved_table}\G` to get the table schema.-->
-        <!-- use `curl -G "http://${tidb-server-ip}:${tidb-server-status-port}/stats/dump/${db_name}/${table_name}" > ${table_name}_stats.json` to get the dumped statistics of one involved table.-->
-    - The `EXPLAIN` result of the compared database. For MySQL, `EXPLAIN format=json`'s result will be more helpful.
-    - Other information that is useful from your perspective.
-
-- For a general performance question, e.g. the benchmark result you got by yourself is not expected, please provide the following information:
-    - Your cluster's topology architecture.
-    - A simple description of you workload.
-    - The metrics PDF generated from Grafana monitor. Remember to set the time range to the performance issue duration.