[REF] survey: clean results page and its code generating statistics

PURPOSE

As new features are about to land in survey, notably live interactions [1]
and new survey building [2] performing a pre cleaning is necessary. In this
PR we clean survey models by: removing unnecessary fields, cleaning some code
and finally renaming models.

SPECIFICATIONS

Purpose of this commit is to globally rewrite the way statistics are
pre computed and used in results page of surveys. Indeed current code is
very complex, having a lot of calls to the same methods while taking only
part of its results. It also have a mix of model and controller methods,
data is computed several times a bit differently, ...

In this commit we rewrite that part. Including

  * a simpler code flow;
  * a simpler data structure;
  * use a better naming for methods instead of "prepare_results" called
    randomly within the code and re-using part of its returned content;
  * use record sets / records instead of giving sub-elements of a record
    like question.title, label.value, ...

Data structure

  * simply give a question_and_page_ids to the template that will iterate
    on pages / questions;
  * have a graph_data, table_data dictionaries available for graph and
    table display with simple entries;
  * graph_data: holding all necessary but minimalist data for graph display
    if question allows it;
  * table_data: holding all necessary but minimalist data for table / summary
    display;
  * hold record sets of done / failed answers and answer lines;

In this commit we also simplify and clean pagination in survey graph results

  * remove page_range helper tool that can be inlined in the templates
    directly, doing a simple range;
  * fix and improve pagination code;

LINKS

[0] Related to Task ID 2061901 (survey models cleaning and preparation)
[1] Task ID 1972640 (live interactions)
[2] Task ID 2119587 (new frontend for building surveys)

PR #40765