修改场景中地图使用方式

[xiaoiver]

re #86
修改后 Scene API 使用方式如下，通过 ESModule 按需引用所需地图实现：

import { Scene, PolygonLayer } from '@antv/l7';
import { AMap } from '@antv/l7-maps';

const scene = new Scene({
  id: 'map',
  map: new AMap({
    center: [110.19382669582967, 50.258134],
    pitch: 0,
    style: 'dark',
    zoom: 3,
    token: 'pg.xxx', // 高德或者 Mapbox 的 token
  }),
});

CDN 用法如下：

const scene = new L7.Scene({
  id: 'map',
  map: new L7.AMap({
    center: [110.19382669582967, 50.258134],
    pitch: 0,
    style: 'dark',
    zoom: 3,
    token: 'pg.xxx', // 高德或者 Mapbox 的 token
  }),
});

文档、examples 和 stories 中都已经替换成最新的 API。

[tests-checker]

Could you please add tests to make sure this change works as expected?

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[lgtm-com]

This pull request introduces 1 alert and fixes 1 when merging 9d08549 into e585bf1 - view on LGTM.com

new alerts:

• 1 for Unused variable, import, function or class

fixed alerts:

• 1 for Unused variable, import, function or class

[lgtm-com]

This pull request introduces 3 alerts and fixes 2 when merging 393e891 into e585bf1 - view on LGTM.com

new alerts:

• 3 for Unused variable, import, function or class

fixed alerts:

• 2 for Unused variable, import, function or class

[lgtm-com]

This pull request introduces 3 alerts and fixes 3 when merging 8943ee6 into e585bf1 - view on LGTM.com

new alerts:

• 3 for Unused variable, import, function or class

fixed alerts:

• 3 for Unused variable, import, function or class

[lgtm-com]

This pull request introduces 8 alerts and fixes 3 when merging 864d73c into e585bf1 - view on LGTM.com

new alerts:

• 8 for Unused variable, import, function or class

fixed alerts:

• 3 for Unused variable, import, function or class

[lgtm-com]

This pull request introduces 9 alerts and fixes 3 when merging 4579a9b into 3c71526 - view on LGTM.com

new alerts:

• 9 for Unused variable, import, function or class

fixed alerts:

• 3 for Unused variable, import, function or class

[lgtm-com]

This pull request introduces 9 alerts and fixes 3 when merging 90537ef into 3c71526 - view on LGTM.com

new alerts:

• 9 for Unused variable, import, function or class

fixed alerts:

• 3 for Unused variable, import, function or class