[Security Solution][DQD] Tech Debt Cleanup

[kapral18]

• cleanup dead code
• flatten scaffold where possible
• restructure react components nesting so that used dependencies are colocated
• DRY code up where it makes sense

[elasticmachine]

Pinging @elastic/security-threat-hunting (Team:Threat Hunting)

[elasticmachine]

Pinging @elastic/security-threat-hunting-explore (Team:Threat Hunting:Explore)