Tests: ensure all netconf requests with identityref have declared namespaces.
* This is part of fixing [Yang identityref XML encoding is not general](https://github.com/clicon/clixon/issues/90)
* This enables full string lexical parsing of some rules previously not fully compliant, including:
* refine
* user-augment
* if-feature
* Also solves previous tokenization issues
[Conversion of ethernet address (PhysAddress) and IP address (IPAddress) crashes agent](https://github.com/clicon/clixon/issues/340)
Hwaddress and IP adress for scalar and table set should now work
Added two new config options to clixon-config.yang: `CLICON_HTTP_DATA_ROOT`
Added new files: apps/snmp/snmp_mib_yang.[ch] for generic MIB/YANG handling
Test: killall quiet
Test: added specific MIB for generic code: <CLICON_SNMP_MIB>NET-SNMP-EXAMPLES-MIB</CLICON_SNMP_MIB>
Added configure option --with-mib-generated-yang-dir=DIR with
default value /usr/share/mibyang where generated YANGs from MIBs
should be placed so that SNMP tests know where to find the YANGs.
* Previous implementation did not handle nested if-feature expressions
* As part of fixing: [YANG if-feature does not support nested boolean expression](https://github.com/clicon/clixon/issues/341)
* Added new yacc/lex parser for if-feature-expr string
* Instead of using prefixes for augmented XML, assign the default namespace
Test: moved datastore format tests from test_cli to new test_datastore_format
Added support for list x y;
Uses a mechanism to parse as unknown XML body and post-parsing replace with list keys
Fixed example and test to work with new TEXT syntax
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 new text syntax parsing and loading from CLI
* Unified text output functions to `xml2txt` and moved to clixon_text_syntax.[ch]
* The following are removed: `cli_xml2txt` and `xml2txt_cb`
* Text output format changed:
* Namespace/modulename added to top-level
* See [Support performant load_config_file(...) for TEXT format](https://github.com/clicon/clixon/issues/324)
