Add name field to signals, instances, ports

[fabianschuiki]

Extend the sig and inst instructions, as well as ports in signatures, to carry an optional name as a quoted string. This makes the SSA value of the instruction less relevant, and gives simulators the opportunity to more precisely track the names in the original HDL.

Example

%1 = sig i1 %0, "clk"
inst @acc.param156 "i_accumulator" (...) -> (...)
entity @foo (i1$ %0 "clk_i") -> (i1$ %1 "clk_no") { ... }