Port SSL init functions for static builds from mamba

[wolfv]

We have a function to initialize SSL on the three different platforms when ca-certificates is not installed in the same prefix.

On Windows, we choose schannel (the native solution), on macOS we use SecureSystem and on Linux we bundle OpenSSL but use the host certificates (as found in some default locations).

Would be cool to port this function to powerloader and use it when necessary:

https://github.com/mamba-org/mamba/blob/e5bb726e02a948f8e97e69a1e371dde6e8824823/libmamba/src/core/fetch.cpp#L21-L136