Add filtering by Cost Centre Id

Adds two new requests if the debuggee program has been compiled with
profiling:

* Request CCS_MAIN location
* Dereference IndexTable

Package `ghc-debug-client` adds utility functions to find CCSPtrs given
a cost centre id, either including all transitive CCS children or only
CCS parts that reference a specific cost centre.

Add UI Filter to `ghc-debug-brick` allowing to list closures that have
been allocated under a specific cost centre.