DOC: Move API to separate section

docs/make.jl

 using Documenter, CaosDB
 
-makedocs(modules = [CaosDB], sitename = "CaosDB.jl Documentation")
+makedocs(
+    modules = [CaosDB],
+    sitename = "CaosDB.jl",
+    format = Documenter.HTML(prettyurls = false),
+    pages = [
+        "Home" => "index.md",
+        "Getting started" => "README_SETUP.md",
+        "Library" => "api.md",
+    ],
+)

docs/src/api.md

+# CaosDB.jl's API
+
+Below you find the explicit documentation of CaosDB's public
+interface. You also find the documentation of the internal API which
+is meant for expert use only. Only use those if you know what you're
+doing.
+
+## Public API
+
+```@autodocs
+Modules=[CaosDB, CaosDB.Exceptions, CaosDB.Info, CaosDB.Utility, CaosDB.Connection, CaosDB.Authentication, CaosDB.Entity]
+Private=false
+```
+
+## Expert-use only API functions
+
+```@autodocs
+Modules=[CaosDB, CaosDB.Exceptions, CaosDB.Info, CaosDB.Utility, CaosDB.Connection, CaosDB.Authentication, CaosDB.Entity]
+Public=false
+```

docs/src/assets/logo.svg

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\ No newline at end of file

docs/src/index.md

 # CaosDB.jl documentation
 
-This will be the index of the documentation of the CaosDB Julia client
-library.
+Welcome to CaosDB.jl, the Julia Client for
+[CaosDB](https://caosdb.org), the opensource research data management
+system. In here you find instruction on how to [Set-up
+CaosDB.jl](@ref) and an overview of [CaosDB.jl's API](@ref).
 
-Manually add a docstring here:
+## Contents
 
-```@docs
-CaosDB.Utility.get_env_var(::AbstractString, ::AbstractString)
-```
-
-
-## Public API
-
-Similar to autodoc:
-
-```@autodocs
-Modules=[CaosDB, CaosDB.Info, CaosDB.Utility, CaosDB.Connection, CaosDB.Authentication, CaosDB.Entity]
-Private=false
-```
-
-## Expert-use only API functions
-
-```@autodocs
-Modules=[CaosDB, CaosDB.Info, CaosDB.Utility, CaosDB.Connection, CaosDB.Authentication, CaosDB.Entity]
-Public=false
+```@contents
+Pages = ["README_SETUP.md", "api.md"]
 ```