Add artwork for first release

The first release needs artwork:

• Logo
• Icon

marked the checklist item Logo as completed

marked the checklist item Logo as incomplete

added prio::1 label

changed milestone to %1.0a0

mentioned in merge request !12 (merged)

removed 1 deleted label

mentioned in issue #17 (closed)

marked the checklist item Logo as completed

mentioned in commit d39cee5b

mentioned in commit 10d7844a

marked the checklist item Icon as completed

changed the description

mentioned in commit e90ba2f8