Update issue templates (#17213)

* Update issue templates

* Rename Custom.md to Z.md

* Create A.md

* Rename A.md to BUG.md

* Rename Z.md to SUPPORT.md

* Create ACTIVATION.md

* Update BUG.md

* Update BUG.md

* Delete ISSUE_TEMPLATE.md

.github/ISSUE_TEMPLATE/ACTIVATION.md

+---
+name: I am having difficulty installing Flutter or getting it to work
+about: You have run into problems while downloading or installing Flutter,
+  or the "flutter" tool is crashing, or you are running into some other
+  issue before even being able to use "flutter run".
+
+---
+
+<!-- Thank you for using Flutter!
+
+     If you are looking for support, please check out our documentation
+     or consider asking a question on Stack Overflow:
+      * https://flutter.io/
+      * https://docs.flutter.io/
+      * https://stackoverflow.com/questions/tagged/flutter?sort=frequent
+
+     If you have found a bug or if our documentation doesn't have an answer
+     to what you're looking for, then fill our the template below. Please read
+     our guide to filing a bug first:  https://flutter.io/bug-reports/
+-->
+
+## Steps to Reproduce
+
+<!-- Please tell us exactly how to reproduce the problem you are running into. -->
+ 
+1. ...
+2. ...
+3. ...
+
+## Logs
+
+<!--
+      Include the full logs of the commands you are running between the lines
+      with the backticks below. If you are running any "flutter" commands,
+      please include the output of running them with "--verbose"; for example,
+      the output of running "flutter --verbose create foo".
+-->
+
+```
+```
+
+<!-- If possible, paste the output of running `flutter doctor -v` here. -->
+
+```
+```

.github/ISSUE_TEMPLATE/BUG.md

+---
+name: I have a problem with my Flutter application.
+about: You are writing an application with Flutter but a widget is rendering
+  incorrectly, the application is crashing, there's an exception in the logs,
+  a widget is behaving badly, or some other such problem is manifesting.
+
+---
+
+<!-- Thank you for using Flutter!
+
+     If you are looking for support, please check out our documentation
+     or consider asking a question on Stack Overflow:
+      * https://flutter.io/
+      * https://docs.flutter.io/
+      * https://stackoverflow.com/questions/tagged/flutter?sort=frequent
+
+     If you have found a bug or if our documentation doesn't have an answer
+     to what you're looking for, then fill our the template below. Please read
+     our guide to filing a bug first:  https://flutter.io/bug-reports/
+-->
+
+## Steps to Reproduce
+
+<!--
+     Please tell us exactly how to reproduce the problem you are running into.
+
+     Please attach a small application (ideally just one main.dart file) that
+     reproduces the problem. You could use https://gist.github.com/ for this.
+
+     If the problem is with your application's rendering, then please attach
+     a screenshot and explain what the problem is.
+-->
+ 
+1. ...
+2. ...
+3. ...
+
+## Logs
+
+<!--
+      Run your application with `flutter run --verbose` and attach all the
+      log output below between the lines with the backticks. If there is an
+      exception, please see if the error message includes enough information
+      to explain how to solve the issue.
+-->
+
+```
+```
+
+<!--
+     Run `flutter analyze` and attach any output of that command below.
+     If there are any analysis errors, try resolving them before filing this issue.
+-->
+
+```
+```
+
+<!-- Finally, paste the output of running `flutter doctor -v` here. -->
+
+```
+```

.github/ISSUE_TEMPLATE/SUPPORT.md

+---
+name: I want help writing my application
+about: You have a question for how to achieve a particular effect, or you need help
+  with using a particular API.
+
+---
+
+<!-- Thank you for using Flutter!
+
+     Please check out our documentation first:
+      * https://flutter.io/
+      * https://docs.flutter.io/
+
+     If you can't find the answer there, please consider asking a question on
+     the Stack Overflow Web site:
+      * https://stackoverflow.com/questions/tagged/flutter?sort=frequent
+
+     Please don't file a GitHub issue for support requests. GitHub issues are
+     for tracking defects in the product. If you file a bug asking for help, we
+     will consider this a request for a documentation update.
+
+-->

ISSUE_TEMPLATE.md

-## Steps to Reproduce
-
-Please tell us what you were doing and what went wrong. If you are running flutter tools from the command line, please try adding the `-v` or `--verbose` option to gather more information.
-
-If the problem is with your application's rendering, please attach a screenshot and any relevant source code.
-If you are getting an exception in the logs, and your code is implicated in the first few frames, then please include the source code for the functions involved.
-
-## Logs
-
-Run your application with `flutter run` and attach all the log output.
-
-Run `flutter analyze` and attach any output of that command also.
-
-## Flutter Doctor
-
-Paste the output of running `flutter doctor -v` here.
-
-> For more information about diagnosing and reporting Flutter bugs, please see [https://flutter.io/bug-reports/](https://flutter.io/bug-reports/).