[Security Solution][Notes] - make the number of note limit customizable in an advanced settings

[PhilippeOberti]

Description

This previous PR added the notion of a maximum number of unassociated notes (see here) to a value of 1000.

We should allow users to customize this value via an advanced settings.

Questions

• should be add a maximum value?

Acceptance criteria

• add an advanced settings to customize the maximum number of notes that can be created

[elasticmachine]

Pinging @elastic/security-solution (Team: SecuritySolution)

[elasticmachine]

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

[elasticmachine]

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