Support for overlaps json operator

Suggestion

The connector support the "contains" json/array operator. This operator select rows which contain ALL value in the array.
I propose the support the "overlaps" json/array operator. This operator select rown which contain ANY value in the array.

Use Cases

With this feature, you will be able to use the JSON Array [array operator &&] operator from PostgreSQL(https://www.postgresql.org/docs/current/functions-array.html).

Examples

Row 1: [ A, B]
Row 2: [C, D]
Row 3: [E, A, B ]
Look for any row which overlaps with [C, F] => Should return Row 2

Acceptance criteria

• Doc
• Test
• Code

It is very easy to implement. Unfortunately, I don't know how to use correctly GitHub for PR. So, I can provide code, and i hope someone will be able to PR it.

/test/postgresql.test.js line 294 -------------

 it('should support the "overlaps" where filter for array type field', async () => {
    await Post.create({
      title: 'Overlaps: LoopBack Participates in Hacktoberfest',
      categories: ['OL_LoopBack', 'OL_Announcements'],
    });
    await Post.create({
      title: 'Overlaps: Growing LoopBack Community',
      categories: ['OL_LoopBack', 'OL_Community'],
    });

    const found = await Post.find({where: {and: [
      {
        categories: {'overlaps': ['OL_Super', 'OL_Community']},
      },
    ]}});
    found.map(p => p.title).should.deepEqual(['Overlaps: Growing LoopBack Community']);
  });

/lib/postgresql.js, line 553 ------------------------------------------------------

case 'overlaps':
  return new ParameterizedSQL(columnName + ' && array[' + operatorValue.map(() => '?') + ']::'
    + propertyDefinition.postgresql.dataType,
  operatorValue);
case 'contains':
  return new ParameterizedSQL(columnName + ' @> array[' + operatorValue.map(() => '?') + ']::'
    + propertyDefin

README.md line 601---------------------------------------------------

Operator overlaps
The overlaps operator allow you to query array properties and pick only
rows where the stored value contains any of the items specified by the query.
The operator is implemented using PostgreSQL array operator &&.
Note The fields you are querying must be setup to use the postgresql array data type - see Defining models above.

从 lib/postgresql.js 第 553 行附近现有的数组运算符处理以及 test/postgresql.test.js 中的相关用例开始。使用 issue 中的示例，为 filter 时发生重叠的情况添加覆盖，然后更新 README.md 第 601 行附近的运算符文档。测试通过且 PostgreSQL 数组重叠行为已有文档说明，即视为完成。