[schemaserial] serialize additional yams parameter for customs type Yams have a new custom type feature. We add support for extra parameter on CWAttribute in schema serialization handling. Closes #2847151

[sql] preprocess_entity uses lgdb helper's SQL converters. The preprocess_entity does not yield anymore the conversion logic for different base types, but relies on a new SQL_CONVERTERS dictionary of the db helper. This will allow later inclusion of new base types.

[repo] kill rebuildinfered feature from Repository.set_schema This clutters thing and is useless in most cases: when schema just have been readen from the database or from the file-system, infered relations have just be calculated. The only use-case where it should be rebuilt is on migration (ie schema modification by editing the meta-model using rql), so move this feature there.

[test] stop deepcopying for nothing

drop xhtml content-type support (closes #2065651) * HTMLStream does not care about xml any more * reqquest.demote_to_html and .xhtml_browser are deprecated * web config: drop force-html-content-type option * adjust tests

[htmlparser] exclude <script> tag from html source lxml are confused by them :-(

[htmlparser] store unaltered source in pageinfo.source Do not store the parser to preserve the source aspect. Store the initial input in the source argument instead. This is very useful when parsing html. In such case we need to drop ``<script>`` tag.

[htmlparser] rename SaxOnlyValidator to XMLValidator