[FIX] web_tip: handles `content changed` event in forms; minor fixes

* eval tip on form content changes
* prevent multiple tip trigerring in some cases
* use scrollTo jquery plugin
[ADD] website: new blog demo snippets

(cherry picked from commit 6c6df546eb5a99d00d62fc6b497b4b861431423e)
(closes #2631)
[IMP]hr_evaluation: remove hr_evaluation.plan, remove hr_evaluation.plan.phase, remove hr_evaluation.interview. add new fields in hr_employee and hr_evaluation. create and update views for hr_employee, hr_evaluation
[IMP]hr_evaluation: improve view and remove commented code. create appraisal stage object and view
[REM]hr_evaluation: remove commented code and remove code for related hr_evaluation.plan,hr_evaluation.plan.phase,hr_evaluation.interview
[IMP]hr_evaluation: updated fields and views. set fields data on onchange

[IMP]hr_evaluation: remove unused import
[IMP]hr_evaluation: add a new template. apprasial mails will be sent with survey link to manager,colleagues,collaborator and self. apprasial form's some fields readonly,when state is not new
[IMP]hr_evaluation: create a cronjob for next appraisal date
[IMP]hr_evaluation: change state, when click on start appraisal button
[IMP]hr_evaluation: Override read_group to always display all states.
[IMP]hr_evaluation: set automatic in manager apprasial list if select send apprasial to manager.
[IMP]hr_evaluation: create url with token. add new fields for total number of sent appraisal and number of completed appraisal. improve typo and view
[IMP]hr_evaluation: Image gauge: number of sent appraisal form and link to answers for this appraisal. link to open calendar to set final meeting and interview date for this appraisal. once it is scheuled, then set the date with the label of final interview.
[IMP]hr_evaluation: constraint for duplicates of same date & year for same employee
[IMP]hr_evaluation: added more dependend fields for function fields. remove appraisal_sent_date fields. improved search_count method
[IMP]hr_evaluation: create yml test for employee evaluation. add followers in followers list, if you change/update manager in appraisal_manager_ids field.
[IMP]hr_evaluation: create access right so an employee can see only own appraisal form if given survey manager rights.
[IMP]hr_evaluation: create a new method to create and update calendar meeting on change of interview date. using default server date format. remove commentd code. remove unused import and improve fields typo in hr_evaluation.
[IMP]hr_evaluation: add typo and help for method. update access rights. create/update hr_evaluation report according to new hr_evaluation. remove hr_evaluation_installer.xml file.
[IMP]hr_evaluation: fix Integrity Error,Tracebak on group by 'Status' and access right issue. Apprisal deleted only from 'To Start' state.