Add namespace search to graphql

[miratepuffin]

What changes were proposed in this pull request?

• Added a new namespace API in graphql which allows you to easily explore the graphs which are present within each path, and explode the childen and parent of each namespace. This will replace the GQLgraphs api which will be deprecated.

Why are the changes needed?

• Pain to currently work out where everything in as you can only query either one graph or all of them so you to do a lot of post processing.

Does this PR introduce any user-facing change? If yes is this documented?

• Yes and to do

How was this patch tested?

• Several new tests on path vailidity making sure users cannot escape the working directory.

Are there any further changes required?

• GqlGraphs needs to be removed

[github-actions]

⚠️ Performance Alert ⚠️

Possible performance regression was detected for benchmark 'Rust Benchmark'.
Benchmark result of this commit is worse than the previous benchmark result exceeding threshold 2.

Benchmark suite	Current: 43f1f68	Previous: 0d81c86	Ratio
lotr_graph/has_node_existing	32 ns/iter (± 2)	13 ns/iter (± 0)	2.46

This comment was automatically generated by workflow using github-action-benchmark.

[ljeub-pometry]

Some minor things to tidy up.
Handling of \ in paths looks like it could give wrong results

[CLAassistant]

All committers have signed the CLA.