Make authority discovery configurable (#7465)

* Make authority discovery configurable

This pr makes the authority discovery configurable. So, instead of
having default values for the query interval, publish interval etc this
pr adds a configuration to make these values changeable. This will be
useful for tests where authority discovery is required.

* Update client/authority-discovery/src/worker.rs

Co-authored-by: Max Inden <[email protected]>

* Update client/authority-discovery/src/lib.rs

Co-authored-by: Max Inden <[email protected]>

* Update client/authority-discovery/src/lib.rs

Co-authored-by: Max Inden <[email protected]>

* Update client/authority-discovery/src/lib.rs

Co-authored-by: Max Inden <[email protected]>

* Fix compilation

* line width

Co-authored-by: Max Inden <[email protected]>