Feature Request: eeschema Docked Hierarchy sheet navigator

Description

Please have the sheet hierarchy navigator persistent in eeschema that can docked in the left side bar for maximum effectiveness. I am using the navigator in another desktop now and it's not that most elegant solution

Steps to reproduce

N/A

KiCad Version

Application: Eeschema
Version: (5.99.0-1660-gc6adfa40e), debug build
Libraries:
    wxWidgets 3.0.4
    libcurl/7.64.1 SecureTransport (LibreSSL/2.8.3) zlib/1.2.11 nghttp2/1.39.2
Platform: macOS Catalina Version 10.15.4 (Build 19E287), 64 bit, Little endian, wxMac
Build Info:
    Build date: May 13 2020 03:36:08
    wxWidgets: 3.0.4 (wchar_t,STL containers,compatible with 2.8)
    Boost: 1.72.0
    OpenCASCADE Community Edition: 6.9.1
    Curl: 7.54.0
    Compiler: Clang 9.0.0 with C++ ABI 1002

Build settings:
    KICAD_SCRIPTING=ON
    KICAD_SCRIPTING_MODULES=ON
    KICAD_SCRIPTING_PYTHON3=OFF
    KICAD_SCRIPTING_WXPYTHON=ON
    KICAD_SCRIPTING_WXPYTHON_PHOENIX=OFF
    KICAD_SCRIPTING_ACTION_MENU=ON
    BUILD_GITHUB_PLUGIN=ON
    KICAD_USE_OCE=ON
    KICAD_USE_OCC=OFF
    KICAD_SPICE=ON
    KICAD_STDLIB_DEBUG=OFF
    KICAD_STDLIB_LIGHT_DEBUG=OFF
    KICAD_SANITIZE=OFF