feat(catalog): add catalog composite

[hugbe8]

Please check if the PR fulfills these requirements

• The commit message follows our guidelines:https://github.com/infra-geo-ouverte/igo2/blob/master/.github/CONTRIBUTING.md#git-commit-guidelines
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

What is the current behavior? (You can also link to an open issue here)

1. A catalog is only a reflection of its service.
2. A layer without group does not appear in the wms catalog
3. The catalog item constructor does not manage nested groups

What is the new behavior?

1. Configure a catalog from several sources (service: wms, wmts, ...) with the possibility of imposing a group in a catalog call
   feat(catalog): add catalog composite

Guideline:

• the groups merge on the identifier "id"
• the layers merge on the identifier "title". On this case:
  • only one layer with same group and same catalogue source is keep
  • an enumeration indicator is used when many layers have the same final group and different origin catalog

Method to use step by step:

• Repare all catalog call. [Catalog1, Catalog2, Catalog3, ...]
• Get all groups and layers for each service catalog call. [CatalogItems[], CatalogItems[], CatalogItems[], ...]
• On the "groupImpose" option, put all the layers flat from a specific catalog in a custom group.
  entrance: [CatalogItems[Group1[layer1, layer2], Group2[layer1, layer4], CatalogItems[], CatalogItems[], ...]
  output: [CatalogItems[GroupImpose[layer1, layer2, layer4], CatalogItems[], CatalogItems[], ...]
• Concat all CatalogItems in a single array list CatalogItems[]
• Merge the groups with same id on the first level only.
• Merge the layers with same title on each group level (as in the guideline).

Config sample:

  "catalog": {
    "sources": [
        {
          id: 'group_impose',
          title: '(composite catalog) group imposed and unique layer title for same source',
          composite: [
            {
              id: 'tq_swtq',
              url: 'https://geoegl.msp.gouv.qc.ca/apis/ws/swtq',
              regFilters: ['zpegt'],
              groupImpose: {id: 'zpegt', title: 'zpegt'}
            },
            {
              id: 'Gououvert',
              url: 'https://geoegl.msp.gouv.qc.ca/apis/ws/igo_gouvouvert.fcgi',
              regFilters: ['zpegt'],
              groupImpose: {id: 'zpegt', title: 'zpegt'}
            },
            {
              id: 'Gououvert',
              url: 'https://geoegl.msp.gouv.qc.ca/apis/ws/igo_gouvouvert.fcgi',
              regFilters: ['zpegt'],
              groupImpose: {id: 'zpegt', title: 'zpegt'}
            },
            {
              id: 'rn_wmts',
              url: 'https://servicesmatriciels.mern.gouv.qc.ca/erdas-iws/ogc/wmts/Cartes_Images',
              type: 'wmts',
              crossOrigin: true,
              matrixSet: 'EPSG_3857',
              version: '1.0.0',
              groupImpose: {id: 'cartetopo', title: 'Carte topo échelle 1/20 000'}
            }
          ]
        },

PrintScreen:

2. The wms layers without group is recover for the catalog
   fix(catalog): get the wms layers without group on first level of catalog

3. Nested groups are retrieved by the catalog builder
   fix(catalog): recursive loop on wms groups on prepare object for catalog.
   N.B: the fix for display the items is not yet applied

Does this PR introduce a breaking change? (check one with "x")

[ ] Yes
[x] No

If this PR contains a breaking change, please describe the impact and migration path for existing applications:

Other information:
The composite catalog is based on the design pattern composite

[hugbe8]

refer to issues:
Resolved: #566, #565
Unresolved: #564