update mobile responsiveness on web UI

[david-kalmakoff]

Fixes https://github.com/gotify/server/issues/716

the following pages had responsiveness issues:

• applications (card overflow)
• clients (card overflow)
• plugins (card overflow, info card word wrapping, and card padding)
• individual plugin (info card word wrapping, and card spacing)

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 79.42%. Comparing base (3f29ded) to head (fc6f6cb). Report is 1 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #720 +/- ## ======================================= Coverage 79.42% 79.42% ======================================= Files 56 56 Lines 2639 2639 ======================================= Hits 2096 2096 Misses 452 452 Partials 91 91 ```

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