Add application description to header of application summary box (backport #2596)

[github-actions]

Backport of #2596

---

Description

Add description to applications. Ensure text does not overflow when sized. Permit user setting of description.

Demo

app-desc.mp4

Commits:

db migration - description column to Applications

update db Application model - add description col

update db view for new column

update backend api for new description field

add description to client API for updating appl'n

front end CRUD for new description field

update unit tests for new description field

update frontend tests for description co

Additional

Docs were reviewed and no immediate changes were necessary BUT there was outdated info present in the Application Concepts. As these were (tenuously) related, I have updated them as part of this PR.
+ 1 typo fixed.

Related Issue(s)

#2279

Checklist

• I have read the contribution guidelines
• Suitable unit/system level tests have been added and they pass
• Documentation has been updated
• Upgrade instructions
• Configuration details
• Concepts
• Changes flowforge.yml?
• Issue/PR raised on flowforge/helm to update ConfigMap Template
• Issue/PR raised on flowforge/CloudProject to update values for Staging/Production

Labels

• Backport needed? -> add the backport label
• Includes a DB migration? -> add the area:migration label