NOTE: This is far from being complete or usable in production.

The parser is modified to expect the "transient" keyword on
contract-level declarations, as well as local variables. Most of the
focus is spent on making the former correct, so YMMV with the latter,
espcially in regards to array/reference handling.

The CompilerContext internally separates storage variables from
transient variables and computes a StorageOffset map for each. This is
used to ensure transient and persistent storage aren't overwriting each
other in the same namespace.

Compiling the Test.sol and TestStorage.sol contracts and diffing the
bytecode results in the SLOAD/SSTORE instructions being replaced by
TLOAD/TSTORE instructions. AFAICT there are unreachable portions of the
bytecode that differ between the two, which presumably relates to the
metadata hash appended by the compiler.

There are certainly a ton of edge cases in regard to properly processing
the AST, but this should suffice for some demos.

mapping(uint256 => uint256) transient myMapping; not processed correctly

- support Transient location in ArrayType and ArrayUtils.
- support location in derivation of Mapping. (mapping might be in a
  storage struct or a transient struct)

--optimize-yul does appear to work, but --optimize removes some transiant operations

…lUtilFunctions