refactor(linux): excluded all non-Linux components from build

* All components which won't build (yet) on Linux are excluded.
  This enables switching to Linux in an application without
  explicitly setting COMPONENTS to main in the main
  CMakeLists.txt.
* ESP Timer provides headers for Linux now
* automatically disabling LWIP in Kconfig if it is not available

doc(linux): brought section
  "Component Linux/Mock Support Overview" up to date

examples/protocols/http_server/simple/CMakeLists.txt

@@ -1,10 +1,5 @@
 # The following lines of boilerplate have to be in your project's CMakeLists
 # in this exact order for cmake to work correctly
 cmake_minimum_required(VERSION 3.16)
-
-if("${IDF_TARGET}" STREQUAL "linux")
-    set(COMPONENTS main)
-endif()
-
 include($ENV{IDF_PATH}/tools/cmake/project.cmake)
 project(simple)