Added basic rfc8527 support, but without support for:
* ds:operational
* with-origin
* clixon/test/test_rfc8527_*.sh
The current level of rfc8527 support is intended to allow commit
operations on the 'candidate' datastore without rewriting the 'startup'
datastore.
* `201 Created` for created resources
* `204 No Content` for replaced resources.
* See [RESTCONF: HTTP return codes are not according to RFC 8040](https://github.com/clicon/clixon/issues/56)
* HTTP `Location:` fields added in RESTCONF POST replies
* For preparation for authorization RFC8341
* Plugins add clixon_plugin_init() and api struct for function pointers, eg:
```
static const struct clixon_plugin_api api = {
"example",
clixon_plugin_init,
...
}
clixon_plugin_api *clixon_plugin_init(clicon_handle h)
{
return (void*)&api;
}
```
* Moved specific plugin functions from apps/ to generic functions in lib/
* New generic plugin load function: clixon_plugins_load()
* Removed client-local netconf plugins netconf_plugin_callbacks()
* This was code used before generic YANG rpc calls
* Added username to clixon handle:
* clicon_username_get() / clicon_username_set()
* Added authentication plugin callback
* Removed some obscure plugin code that seem not to be used (please report if needed!)
* CLI parse hook
* CLICON_FIND_PLUGIN
* clicon_valcb()
* Removed username to rpc calls (added below)
