Ordering and sizing of dashboards

Implement a method for ordering and sizing dashboard widgets, both to be defined by the widget class, and, if aplicable, adjustable per user.

• Sizing (system-wide)
• Default ordering (system-wide)
• Per-user ordering

changed milestone to %2.0a2

added part::backend part::frontend type::feature workflow::confirmed labels

mentioned in issue #175 (closed)

assigned to @ZugBahnHof

unassigned @ZugBahnHof

removed milestone

mentioned in merge request !409 (merged)

changed the description

created merge request !410 (merged) to address this issue

mentioned in merge request !410 (merged)

marked the checklist item Sizing (system-wide) as completed

mentioned in merge request !411 (merged)

assigned to @hansegucker

marked the checklist item Per-user ordering as completed

marked the checklist item Default ordering (system-wide) as completed

closed with merge request !411 (merged)

mentioned in commit 70b39a38