Update developer docs to no longer support VCPKG_ROOT as a mechanism to set/find global versions of the vcpkg repo

[ahsonkhan]

Similar to Azure/azure-sdk-for-c#2404, consider updating AzureVcpkg.cmake to no longer support VCPKG_ROOT as a mechanism to set where the vcpkg registry is located locally.

azure-sdk-for-cpp/tools/AzureVcpkg.cmake

Lines 5 to 19 in d1b05c2

	# AUTO CMAKE_TOOLCHAIN_FILE:
	# User can call `cmake -DCMAKE_TOOLCHAIN_FILE="path_to_the_toolchain"` as the most specific scenario.
	# An env var VCPKG_ROOT or VCPKG_INSTALLATION_ROOT can be set to let Azure SDK to set the VCPKG toolchain automatically.
	# As the last alternative (default case), Azure SDK will automatically clone VCPKG folder and set toolchain from there.
	if(NOT DEFINED CMAKE_TOOLCHAIN_FILE)
	if(DEFINED ENV{VCPKG_ROOT})
	set(CMAKE_TOOLCHAIN_FILE "$ENV{VCPKG_ROOT}/scripts/buildsystems/vcpkg.cmake"
	CACHE STRING "")
	elseif(DEFINED ENV{VCPKG_INSTALLATION_ROOT})
	set(CMAKE_TOOLCHAIN_FILE "$ENV{VCPKG_INSTALLATION_ROOT}/scripts/buildsystems/vcpkg.cmake"
	CACHE STRING "")
	else()
	# Set AZURE_SDK_DISABLE_AUTO_VCPKG env var to avoid Azure SDK from cloning and setting VCPKG automatically
	# This option delegate package's dependencies installation to user.
	if(NOT DEFINED ENV{AZURE_SDK_DISABLE_AUTO_VCPKG})

[github-actions]

Hi @ahsonkhan, we deeply appreciate your input into this project. Regrettably, this issue has remained unresolved for over 2 years and inactive for 30 days, leading us to the decision to close it. We've implemented this policy to maintain the relevance of our issue queue and facilitate easier navigation for new contributors. If you still believe this topic requires attention, please feel free to create a new issue, referencing this one. Thank you for your understanding and ongoing support.