Feat/graph coloring ambiguity issue

[iremozs]

Description

• Added a legend for the topic node coloring
• Added the topic name when hovered over a node
• Adjusted the backend to return a maximum of given number of topics and pack the rest into topic name "others", with default max_topics set to 25.
• Added a combined color scheme with a total number of 30 different colors.

Related Backlog Item

Issue: #181

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Context

• The users understand what the node coloring means.

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Checklist:

• I have documented my changes
• I have tested the changes and they work as expected
• I have assigned this PR to someone
• I have run make format to format my code

Additional references

[nikolas-rauscher]

i added it to the new codebase