cloud-setup: Add OCI (Oracle Cloud) provider

Initial support for OCI. It doesn't support VLAN configuration yet as
the requirements are not clear. It doesn't support secondary IP
addresses because the IMDS server doesn't expose them.

Instead of using plain text format, it gets a single response in JSON
format and parses it. The dependency to jansson is now mandatory for
that.

meson.build

@@ -800,6 +800,7 @@ endif
 enable_nm_cloud_setup = get_option('nm_cloud_setup')
 if enable_nm_cloud_setup
   assert(libcurl_dep.found(), 'nm-cloud-setup requires libcurl library. Use -Dnm_cloud_setup=false to disable it')
+  assert(jansson_dep.found(), 'nm-cloud-setup requires jansson library. Use -Dnm_cloud_setup=false to disable it')
 endif
 
 enable_docs = get_option('docs')