Add issue button w/ some button updates (#221)

In this PR, I've added a "Report an issue" button and a few more
button-related changes:
- Add "Report an issue" button
- Add icon for "Octobot's source code"
- Rename `AboutTitleRepository` to `ButtonOpenRepository`
- Rename `OpenEventInfoButton` to `ButtonOpenEventInfo` to be consistent
with other language string names
- Rename `ColorsList.cs` to `Miscellaneous.cs`
- Add public const strings in `Octobot.cs` to get repository & issues links

---------

Signed-off-by: mctaylors <cantsendmails@mctaylors.ru>

locale/Messages.resx

@@ -348,7 +348,7 @@
   <data name="DescriptionExternalEventCreated" xml:space="preserve">
     <value>The event will start at {0} until {1} in {2}</value>
   </data>
-  <data name="OpenEventInfoButton" xml:space="preserve">
+  <data name="ButtonOpenEventInfo" xml:space="preserve">
       <value>Open Event Info</value>
   </data>
   <data name="EventDuration" xml:space="preserve">
@@ -396,7 +396,7 @@
   <data name="AboutTitleDevelopers" xml:space="preserve">
     <value>Developers:</value>
   </data>
-  <data name="AboutTitleRepository" xml:space="preserve">
+  <data name="ButtonOpenRepository" xml:space="preserve">
     <value>Octobot's source code</value>
   </data>
   <data name="AboutBot" xml:space="preserve">
@@ -582,4 +582,7 @@
   <data name="ContactDevelopers" xml:space="preserve">
       <value>Contact the developers if the problem occurs again.</value>
   </data>
+  <data name="ButtonReportIssue" xml:space="preserve">
+      <value>Report an issue</value>
+  </data>
 </root>