conan_provider.cmake: update and add support for auto-downloading of Conan client

[valgur]

Updates conan_provider.cmake to the latest official version and adds the unmerged changes from this PR: conan-io/cmake-conan#651

After these changes, the Conan client is downloaded automatically if it is not found on the system or if its version is too old:

-- CMake-Conan: Downloading Conan 2.5.0 from https://github.com/conan-io/conan/releases/download/2.5.0/conan-2.5.0-linux-x86_64.tgz
-- CMake-Conan: Setting CONAN_HOME to '/home/runner/work/novatel_edie/novatel_edie/build/conan_home'
-- CMake-Conan: first find_package() found. Installing dependencies with Conan
-- CMake-Conan: Checking if a default profile exists
...

After these changes you should only need a compiler toolchain and CMake as a prerequisite to build novatel_edie.