Add ignore button on app update screen

[flxholle]

Just added a "IGNORE" button in the app update screen. See #281

[m-rey]

Any progress/review on this PR? Such a feature would be awesome.

For example, often times the signature of an app update and the signature of the currently installed application differ. In those cases, an update without data loss is not easily possible. Cirrently I try to update the apps, notice the signature mismatch and then manually ignore the update.

Adding an "ignore" button to hide the update would declutter the list and help a lot when updating applications.