fix: performance of cube-projects resource

[tpluscode]

TL;DR; a query was generated to load projects' mapping resources in a single request. That request used many FROM claueses

CONSTRUCT { ?s ?p ?o }
FROM <A>
FROM <B>
FROM <C>
FROM <D>
# FROM ...
WHERE { ?s ?p ?o }

This proved to be slow as the number of graphs grow. On the other hand this is fast

CONSTRUCT { ?s ?p ?o }
WHERE {
  { GRAPH <A> { ?s ?p ?o } }
  UNION
  { GRAPH <B> { ?s ?p ?o } }
  UNION
  { GRAPH <C> { ?s ?p ?o } }
  UNION
  { GRAPH <D> { ?s ?p ?o } }
  # UNION ...
}

[changeset-bot[bot]]

🦋 Changeset detected

Latest commit: 4601dab7e2db24697205066eb644951e46b0f555

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

| Name | Type | | ---------------------- | ----- | | @cube-creator/core-api | Patch |

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[codecov-commenter]

Codecov Report

Merging #1287 (4601dab) into master (bb16f13) will not change coverage. The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1287   +/-   ##
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  Coverage   81.50%   81.50%           
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  Files         192      192           
  Lines       13379    13379           
  Branches      750      750           
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  Hits        10905    10905           
  Misses       2467     2467           
  Partials        7        7           

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[l00mi]

Are there any Side effects to be expected with this PR?

[tpluscode]

Don't think so. The important change is here.

The queries should be equivalent whether using FROM or UNION GRAPH