* davix: add versions 0.8.2-0.8.7 and dependencies
This commit adds new versions 0.8.2-0.8.7 of the davix package, and it
also improves the handling of embedded packages. Davix will try to build
libcurl from its own embedded version of that code, which doesn't mesh
well with Spack's design philosophy, so I've changed the CMake
configuration to disallow the builtin libcurl and use a Spack dependency
instead. Up to version 0.8.7, RapidJSON was also builtin, but version
0.8.7 allows users to specify that they want to use a pre-installed
version of RapidJSON, so this commit also adds that as a dependency for
versions 0.8.7:.
* Fix old versions
fff8165f2f