Git: Add input validation to RemoteAdditionDialog

Use FancyLineEdits to indicate invalid inputs for
remote names and URLs.

For remote names:
* Check for duplicate remote names and indicate these
* Remove invalid chars during input

For remote URLs:
* Check if the input matches a valid URL or
  existing local directory

Task-number: QTCREATORBUG-15998
Change-Id: I224e669f16e34e2cd3d075c602b431ce5bbdd391
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

src/plugins/git/remotemodel.cpp

@@ -27,6 +27,8 @@
 #include "gitplugin.h"
 #include "gitclient.h"
 
+#include <utils/algorithm.h>
+
 namespace Git {
 namespace Internal {
 
@@ -34,6 +36,11 @@ namespace Internal {
 RemoteModel::RemoteModel(QObject *parent) : QAbstractTableModel(parent)
 { }
 
+QStringList RemoteModel::allRemoteNames() const
+{
+    return Utils::transform(m_remotes, std::mem_fn(&Remote::name));
+}
+
 QString RemoteModel::remoteName(int row) const
 {
     return m_remotes.at(row).name;