Allow dynamic update of agent parameters

[amuraru]

Made the agent profilers re-entrant allowing to attach and update profiling parameters at runtime

This is useful when the VM is not started with the agent but can be later attached and controlled, e.g:

• update profiling interval
• enabling/disabling profilers

For time being only profilers parameters can be updated. Transformers, reporter not

[CLAassistant]

All committers have signed the CLA.

[amuraru]

@boy-uber is this something you wanna integrate? Tx