[fti] refactor and fix full text indexation handling
* moved logic from repository to the native source
* avoid creating a FTIndexOp when no full text indexation is needed
* entities with fulltext_container set are not indexed even when not
related to a container
* avoid duplicated unindexation
debian/tmp/usr/lib/PY_VERSION/site-packages/cubicweb/common/ usr/lib/PY_VERSION/site-packages/cubicweb
debian/tmp/usr/lib/PY_VERSION/site-packages/cubicweb/entities/ usr/lib/PY_VERSION/site-packages/cubicweb
debian/tmp/usr/lib/PY_VERSION/site-packages/cubicweb/ext/ usr/lib/PY_VERSION/site-packages/cubicweb
debian/tmp/usr/share/cubicweb/cubes/shared/i18n usr/share/cubicweb/cubes/shared/
debian/tmp/usr/lib/PY_VERSION/site-packages/cubicweb/*.py usr/share/pyshared/cubicweb