(videoVLC): use absolute path for vlc plugins dir

What does this MR do?

• use absolute path to find VLC plugins dir in videoVLC in installed applications
• fix cmake install target on Windows (with MSVC2019) for application using libvlc:
  • on Windows VLC is now manually installed to avoid fatal error LNK1328: missing string table in fixup_bundle

How to test it?

• package an application (ExVLCVideoStreaming for ex) using videoVLC:

> ninja install
> ninja package

• install and run this application on a machine without a dev environment

Data

• no data required

Associated issue

• Closes #425 (closed)

Required MR

• conan/conan-vlc!9