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.
* The existing autocli does not support modes, complete paths must be given, eg: `set a b c d 42`.
* In the new auto-cli, automatic modes are present at each YANG syntax node level, eg the above can be given as: `edit a b c; set d 4; top`
* The existing CLI API remains, the new API is as follows: `cli_auto_edit()`, `cli_auto_up()`, `cli_auto_top()`, `cli_auto_show()`, `cli_auto_set()`, `cli_auto_merge()`, `cli_auto_create()`, `cli_auto_del()`.
* See `test/test_cli_auto.sh` for an example of the new API, and `apps/cli/cli_auto.c` for the source code of the new callback API.
* Documentation will be appear and full integration with the main example.
* Added inline state field to clixon-example.yang
* Added new clicon_data_cvec_*() API for generic cvec structs
* A new configuration option `CLICON_CONFIGDIR` has been added for loading of extra config files
* If not given, only the main configfile is loaded.
* If given, and if the directory exists, the files in this directory will be loaded alphabetically AFTER the main config file in the following way:
* leaf values are overwritten
* leaf-list values are appended
* You can override file setting with `-E <dir>` command-line option.
* New clixon-config@2020-10-01.yang revision
* Added option for configuration directory: `CLICON_CONFIGDIR`
* If multiple strings (eg "\n" in text), indent before each new line
* Primarily for auto-cli where long help strings are generated from YANG descriptions, but applies as well for manual long/multi-line help strings
* New config option: `CLICON_CLI_HELPSTRING_TRUNCATE`: Truncate help string on right margin mode
* New config option: `CLICON_CLI_HELPSTRING_LINES`: Limit of number of help strings to show
* Only requests on the form: `<rpc xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"><edit-config>...` will be accepted
* All replies will be on the form: `<rpc-reply xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">...`
* Requests such as: `<rpc><edit-config>...` will not be accepted.
* You can revert this behaviour (to clixon pre-4.6 behaviour) by enabling `CLICON_NAMESPACE_NETCONF_DEFAULT`
* This API change is a consequence of: [copy-config's RPC cxobj parameter does not contain namespace #131](https://github.com/clicon/clixon/issues/131)
