Require NetworkManager 1.4.0 and newer
Summary:
NM 1.4.0 was released in 2016, even Debian stable has newer version in repositories
so it shouldn't be problem to require it. We can remove almost all checks for NM
versions and it will also simplify code for upcoming changes.
Reviewers: Frameworks, sitter
Reviewed By: sitter
Subscribers: kde-frameworks-devel, Frameworks
Tags: Frameworks
Differential Revision: https://phabricator.kde.org/D12493