New `ca_system_only` backend callback for reading system-only data
New `CLICON_XMLDB_SYSTEM_ONLY_CONFIG` configuration option
API: Added `system_only` parameter to clixon_xml2file1()
Cleared running on commit and inited candidate on startup with system-only data
Added callback code in main example
* RFC 8528 yang schema mount-points:
* Made expand_dbvar and cli_dbxml mountpoint-aware (RFC 8528)
* autocli supportgenerate
* Made api_path2xml and xml2api_path mount-point-aware
* Temporar fix in clixon_custom.h: XPATH_CANONICAL_SKIP_CHECK
* `xml2xpath()`: Added `apostrophe` as 4th parameter, default 0
* removed extra assert.h includes
* Added flag names: `CLIXON_DBG_*`
* Added maskable flags that can be combined when debugging:
* `DEFAULT` = 1: Basic debug message, espcially initialization
* `MSG` = 2: Input and output packets, read datastore
* `DETAIL` = 4: Details: message dump in hex, xpath parse trees, etc
* `EXTRA` = 8: Extra detailed logs
* Test: some errors in yang-lib where content-id was in wrong place
- fixed typo preventing evaluation of confirmed-commit logic in backend_startup
- fixed uninitialized variable warnings
- added details to CHANGELOG.MD
- added capabilities advertisement for confirmed-commit 1.0 and 1.1
- added xml hello message that uses only eom framing, for simplicity in asynch tests
- add stty restore after wait_restconf to fix console corruption in tests
- adjust test_confirmed_commit to drop perms and run as the invoking user. This will require running user to have permissions on /usr/local/var/example
- added CLI tests
New API is as follows:
* `clixon_xml2file()` - Print internal tree as XML to file
* `clixon_xml2cbuf()` - Print internal tree as XML to buffer
* `clixon_json2file()` - Print internal tree as JSON to file
* `clixon_json2cbuf()` - Print internal tree as JSON to buffer
* `clixon_cli2file()` - Print internal tree as CLI format to file
* `clixon_txt2file()` - Print internal tree as text format to file
* Added `skiptop` parameter, if set only apply to children of a node, skip top node
* default is 0
* Functions are merged, ie removed and replaced with more generic functions
* `xml2json_cbuf()`: Added `skiptop` parameter: `xml2json_cbuf(..., int skiptop)`
* `xml2json()` and `xml2json_cb()` merged into `xml2json_file()` with `skiptop`
* Replace `xml2json(...)` with `xml2json_file(..., stdout, 0)`
* Replace `xml2json_cb(...)` with `xml2json_file(..., 0)`
* `clicon_xml2cbuf()`: Added `skiptop` parameter: `clicon_xml2cbuf(..., int skiptop)`
* `xml2cli()`: Added `skiptop` parameter: `xml2cli(..., int skiptop)`
