Notification for developer build and when new versions are available

This is tweak to the startup screen.

If the version someone is running a a development version, it will say "dev build" by the Start title. I have a link for now taking people to a bug page for the dev build. We might want to change this to something else.

If someone is connected to the internet and there is a newer version of Krita available, a message will appear telling them. They can click on the link to the news article.

Also added tracking so we know how many people are clicking these links.

Test Plan

Tested with a dev build to make sure the message appears. It checks the application version has a
I modified a couple variables to force the "new version available" text and made sure link worked.

Formalities Checklist

• I confirmed this builds.
• I confirmed Krita ran and the relevant functions work.
• I tested the relevant unit tests and can confirm they are not broken. (If not possible, don't hesitate to ask for help!)
• I made sure my commits build individually and have good descriptions as per KDE guidelines.
• I made sure my code conforms to the standards set in the HACKING file.
• I can confirm the code is licensed and attributed appropriately, and that unattributed code is mine, as per KDE Licensing Policy.