Split schemas from DashboardList v2

[api-clients-generation-pipeline]

See DataDog/datadog-api-spec#423

[therve]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[codecov]

Codecov Report

Merging #323 into master will decrease coverage by 0.17%.
The diff coverage is 21.38%.

Impacted Files	Coverage Δ	Complexity Δ
...datadog/api/v2/client/model/DashboardListItem.java	29.03% <ø> (-11.30%)	15.00 <0.00> (-5.00)
...api/v2/client/model/DashboardListItemResponse.java	16.66% <16.66%> (ø)	3.00 <3.00> (?)
.../v2/client/model/DashboardListAddItemsRequest.java	19.23% <19.23%> (ø)	3.00 <3.00> (?)
.../client/model/DashboardListDeleteItemsRequest.java	19.23% <19.23%> (ø)	3.00 <3.00> (?)
.../client/model/DashboardListUpdateItemsRequest.java	19.23% <19.23%> (ø)	3.00 <3.00> (?)
...client/model/DashboardListUpdateItemsResponse.java	19.23% <19.23%> (ø)	3.00 <3.00> (?)
.../api/v2/client/model/DashboardListItemRequest.java	25.00% <25.00%> (ø)	5.00 <5.00> (?)
...m/datadog/api/v2/client/api/DashboardListsApi.java	83.03% <100.00%> (ø)	9.00 <0.00> (ø)
...v2/client/model/DashboardListAddItemsResponse.java	19.23% <100.00%> (ø)	3.00 <0.00> (ø)
...client/model/DashboardListDeleteItemsResponse.java	19.23% <100.00%> (ø)	3.00 <0.00> (ø)
... and 10 more

[therve]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).