updated apps screenshots

[Mik-TF]

Related Issue

• 548

Work Done

• updated screenshots for apps
• added troubleshooting info for bad gateway
• removed owncloud since it's not on the dashboard currently

[Mik-TF]

@maayarosama

If you meant the new UI on dev net in this issue, we can just merge this PR and I will make a new PR for the latest UI on devnet.