Add categories and tags custom models

- app/models/categories.js: remove taxonomy/term models and use specialized model
- app/models/tags.js: remove taxonomy/term models and use specialized model
- app/models/pages.js: add views and updated date fields
- app/models/posts.js: add views and updated date fields
- app/models/comments.js: add updated date field
- app/models/users.js: add last login date field
- app/routes/api.js: add categories and tags routes
- app/routes/api.js: fix authenticated flag for auth by token
- app/routes/pages.js: add views and updated date fields support
- app/routes/posts.js: add views and updated date fields support
- app/routes/comment.js: add updated date fields support
- app/routes/api/*.js: fix updateAttributes() calls
- app/routes/api/*.js: fix auth check to use authenticated state
- app/routes/api/*.js: fix owner check to continue if no owner field is defined
- app/routes/api/*.js: fix offset/limit parameters validation
- app/routes/api/auth/*.js: fix bug account/user code
- app/routes/api/auth/*.js: update user last login
- app/routes/auth.js: keep a list of logged users
- app/routes/status.js: add OS infos
- bin/shell: fix enable anonymous user
- bin/shell: fix categories/tags models and remove taxonomy/terms models

Signed-off-by: Boris HUISGEN <bhuisgen@hbis.fr>