Check if session description exists in edit dialog

Closes #412

See merge request !403

Resolve "Optimize layout of projector icon"

Closes #413

See merge request !402

Set correct role after session creation

Closes #410

See merge request !394

Revert "Merge branch 'staging' into 'master'"

See merge request !400

This reverts merge request !399

change projector icon color

See merge request !399

change projector icon color

See merge request !398

Merge branch '403-the-display-of-the-entered-characters-and-the-maximum-number-of-characters-is-missing-in-the-session-settings' into 'master'

Add hint to session edit

Closes #403

See merge request !395

Resolve "Role-related identifiers and icons for account menu"

Closes #401

See merge request !396

Fix account-deletion dialog

Closes #398, #399, and #400

See merge request !397

Comment icon bar improvements

Closes #407

See merge request !393

Remove superfuous icon for time

See merge request !392

some corrections in domain model

See merge request !391

Correct use cases

See merge request !390

Change 'blog' to 'help' and adjust icon in footer

Closes #402

See merge request !389

Fix comment export

Closes #406

See merge request !388