Slider Server on Windows

[lungben]

Hi Panayiotis,

run_directory does not work for me in Windows (but it does in WSL):

julia> PlutoSliderServer.run_directory("./tmp")
ERROR: SystemError: opening file "mathematics.jl": No such file or directory
Stacktrace:
  [1] systemerror(p::String, errno::Int32; extrainfo::Nothing)
    @ Base .\error.jl:168
  [2] #systemerror#62
    @ .\error.jl:167 [inlined]
  [3] systemerror
    @ .\error.jl:167 [inlined]
  [4] open(fname::String; lock::Bool, read::Nothing, write::Nothing, create::Nothing, truncate::Nothing, append::Nothing)
    @ Base .\iostream.jl:293
  [5] open
    @ .\iostream.jl:282 [inlined]
  [6] open(f::Base.var"#334#335"{Bool}, args::String; kwargs::Base.Iterators.Pairs{Union{}, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
    @ Base .\io.jl:328
  [7] open
    @ .\io.jl:328 [inlined]
  [8] #readline#333
    @ .\io.jl:501 [inlined]
  [9] readline
    @ .\io.jl:501 [inlined]
 [10] is_pluto_notebook
    @ C:\Users\d90394\.julia\packages\Pluto\2OVqf\src\notebook\PathHelpers.jl:97 [inlined]
 [11] filter(f::typeof(Pluto.is_pluto_notebook), a::Vector{String})
    @ Base .\array.jl:2507
 [12] find_notebook_files_recursive
    @ C:\Users\d90394\.julia\packages\PlutoSliderServer\Vw5VT\src\FileHelpers.jl:19 [inlined]
 [13] run_directory(start_dir::String)
    @ PlutoSliderServer C:\Users\d90394\.julia\packages\PlutoSliderServer\Vw5VT\src\PlutoSliderServer.jl:102
 [14] top-level scope
    @ REPL[5]:1

Running a single notebook works (PlutoSliderServer.run_notebook("./tmp\\mathematics.jl")).

Although I think that most people will run the server in Linux (Docker), it would be good to support Windows, too.

[fonsp]

I am actually deprecating Windows support in #11 because it requires some careful attention on using the right path separator for paths vs for URLs...

[lungben]

I think this is fine for now, but in the future it may be worth to re-introduce Windows support.
In corporate environments, Windows is very common and Docker not always available. Especially dev computers usually run on Windows (without WSL available).