Add issue and PR templates

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,17 @@
+Please use this issue tracker only for the build script related bugs and enhancements, such as:
+
+ - requesting changes to the kernel configuration,
+ - requesting changes to the default package lists,
+ - discussing the kernel and/or u-boot patches,
+ - discussing Armbian specific customizations made at image build time,
+ - discussing changes and enhancements to the image creation process,
+ - etc.
+
+Please use the Armbian forum (https://forum.armbian.com/) for:
+
+ - reporting boot failures (please read [the documentation](https://docs.armbian.com/User-Guide_Getting-Started/) first!),
+ - asking for help with Armbian if it is **not** related to building the kernel and/or OS image (please use forum search and Google search first!),
+ - asking for support of new boards or third party hardware (such as wireless and DVB adapters),
+ - etc.
+
+Please remove the text above before opening an issue.

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,7 @@
+Please make sure that:
+
+ - any changes to kernel configuration files were made by Kconfig menu (build script option `KERNEL_CONFIGURE=yes`) and not by editing configuration files by hand,
+ - patch file names don't contain spaces and have less than 40 characters (not counting the `.patch` extension),
+ - changes are properly described - what was done exactly and why.
+
+Thanks for contributing! Please remove the text above before opening a pull request.