Remove "Exposed Webapp" in apps table

[githubsaturn]

This is a useless column and does not provide any meaningful information. If the app is not exposed via a webapp and link icon is not present. Hence this column is just redundant.

Instead, we can use the space and have one/some of the following:

• The currently deployed image name + tag
• The last deploy timestamp
• Whether it's building or not

Other useful information that we may want to add (currently unavailable in the API)

• Running since xxx hr ago
• Last updated timestamp