Hotkeys: change default setting: GoToParent (Alt+P, instead of Ctrl+C), GoToChild (Alt+C, instead of Ctrl+C)

This makes the key settings more consistent to the Next/PrevQuickSearch which also use Alt as modifier. And it makes Ctrl+C free for more intuitive operation: copy to clipboard.
default key setting for ToggleHighlightSelectedBranch: Ctrl+Shift+B
Hotkeys: use Ctrl+C to copy commit hash to clipboard
FormBrowse: File tree / diff Tab: fix "Open containing folder" behaviour
Hotkeys: change default setting: GoToParent (Ctrl+P), GoToChild (Ctrl+N (= next))
FormArchive: update GUI to support <path> argument
FormArchive: implement <path> argument
FormArchive: scrollbars and minimum size
FormArchive: ignore empty path lines
Add "Archive..." to context menu of File tree tab
Merge branch 'pr/n1867_feinstaub'

Conflicts:
	GitUI/GitUI.csproj
Move FormBrowseUtil to GitUI.CommandsDialogs.BrowseDialog
Merge branch 'pr/n1868_feinstaub'

Conflicts:
	GitUI/GitUICommands.cs
Merge pull request #1865 from feinstaub/feature/keyboardshortcut_Ctrl_C

Hotkeys: use Ctrl+C to copy commit hash to clipboard