Show the list of children in the commit details (#710)

* feature: add children list to the commit base info view

Useful for navigation between the commits.

* feature: use repository filters to limit children search
* feature: execute children search asynchronously
* feature: respect global commit limit for a good measure
* fix: input lines may contain several commits

The first commit is always the immediate child, so take only 40 initial characters of the line

* fix: hide children behind the preference
* feature: make parents and children scrollable

src/Views/CommitDetail.axaml

@@ -24,6 +24,7 @@
                             SignInfo="{Binding SignInfo}"
                             SupportsContainsIn="True"
                             WebLinks="{Binding WebLinks}"
+                            Children="{Binding Children}"
                             IssueTrackerRules="{Binding IssueTrackerRules}"/>
 
           <!-- Line -->