Add issue templates and a user support page

This will hopefully help directing our users to better user support
resources as well as give some relevant advice in issue templates.

https://help.github.com/articles/setting-up-your-project-for-healthy-contributions/

Reviewed-by: Nicola Tuveri <nic.tuv@gmail.com>
Reviewed-by: Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
(Merged from https://github.com/openssl/openssl/pull/7623)

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,27 @@
+<!--
+NOTE:
+
+    If you're asking about how to use OpenSSL, this isn't the right 
+    forum.  Please see our
+    [User Support resources](https://github.com/openssl/openssl/blob/master/.github/SUPPORT.md)
+
+If relevant, please remember to tell us in what OpenSSL version you
+found the issue.
+
+Please remember to put ``` lines before and after any commands plus
+output and code, like this:
+
+    ```
+    $ echo output output output
+    output output output
+    ```
+
+    ```
+    #include <stdio.h>
+    
+    int main() {
+        int foo = 1;
+        printf("%d\n", foo);
+    }
+    ```
+-->

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,51 @@
+---
+name: Bug report
+about: Report a defect in the software
+
+---
+
+<!--
+Thank you for your bug report.
+
+NOTE:
+
+    If you're asking about how to use OpenSSL, this isn't the right 
+    forum.  Please see our
+    [User Support resources](https://github.com/openssl/openssl/blob/master/.github/SUPPORT.md)
+
+Please remember to tell us in what OpenSSL version you found the issue.
+
+For build issues:
+
+    If this is a build issue, please include the configuration output
+    as well as a log of all errors.  Don't forget to include the exact
+    commands you typed.
+
+    With OpenSSL before 1.1.1, the configuration output comes from the
+    configuration command.  With OpenSSL 1.1.1 and on, it's the output
+    of `perl configdata.pm --dump`
+
+For other issues:
+
+    If it isn't a build issue, example code or commands to reproduce
+    the issue is highly appreciated.
+    Also, please remember to tell us if you worked with your own
+    OpenSSL build or if it is system provided.
+
+Please remember to put ``` lines before and after any commands plus
+output and code, like this:
+
+    ```
+    $ echo output output output
+    output output output
+    ```
+
+    ```
+    #include <stdio.h>
+    
+    int main() {
+        int foo = 1;
+        printf("%d\n", foo);
+    }
+    ```
+-->

.github/ISSUE_TEMPLATE/feature_request.md

@@ -0,0 +1,32 @@
+---
+name: Feature request
+about: Propose a feature you would like to see added in the software
+
+---
+
+<!--
+Thank you for your feature request.
+
+NOTE:
+
+    If you're asking about how to use OpenSSL, this isn't the right 
+    forum.  Please see our
+    [User Support resources](https://github.com/openssl/openssl/blob/master/.github/SUPPORT.md)
+
+Please remember to put ``` lines before and after any commands plus
+output and code, like this:
+
+    ```
+    $ echo output output output
+    output output output
+    ```
+
+    ```
+    #include <stdio.h>
+    
+    int main() {
+        int foo = 1;
+        printf("%d\n", foo);
+    }
+    ```
+-->

.github/SUPPORT.md

@@ -0,0 +1,11 @@
+OpenSSL User Support resources
+==============================
+
+For *questions* on how to use OpenSSL or what went wrong when you
+tried something, our primary resource is the mailing list
+openssl-users@openssl.org, where you can get help from others in the
+OpenSSL community (which includes the developers as time permits).
+
+Only subscribers can post to openssl-users@openssl.org (although the
+archives are public).
+For more information, see https://www.openssl.org/community/mailinglists.html