[inetstack] Support Fast Lookup for Bound Addresses and Ports

[ppenna]

Context

We currently miss a fast lookup mechanism to determine whether or not a given address/port pair is bound.

Proposed Solution

We should introduce some structure that would enable us to quickly determine if a given address/port pair is bound.

Alternative Solutions

We can consider refactoring existing structures to provide this semantic.

[BrianZill]

Whatever solution we end up with here should support matching the unspecified address (a.k.a. INADDR_ANY) with any specific address. See Issue demikernel/demikernel#189.