[WIP] Pim 2948 : Manage more than 100 options for an attribute type select

| Q                    | A
| -------------------- | ---
| Bug fix?             | N
| New feature?         | Y/N
| BC breaks?           | Y
| CI currently passes? | ?
| Tests pass?          | ?
| Scenarios pass?      | ?
| Checkstyle issues?*  | N
| PMD issues?**        | N
| Changelog updated?   | N
| Fixed tickets        | PIM-2948
| DB schema updated?   | N
| Migration script?    | N
| Doc PR               | 

Left to do : 

| Task                                              | Status
| ------------------------------------------------- | ------
| Use a dedicated serializer for 'UI' serialization | :-1:
| Create an attributeOptionMananger                 | :-1:
| Localize javascript errors                        | :-1:
| Add the "Save first before add any options"       | :-1:
Ok for an AttributeOptionManager but in this case, you've to move some methods from AttributeManager. AttributeManager is the class where attribute options management is done today, so I think you should take a look at ;)