resolc crate (#328)

- Factor the YUL crate out of `revive-solidity`.
- `revive-solidity` is in reality not a Solidity implementation but the
revive solidity compiler driver (`resolc`). By renaming we not only get
this straight but also a binary with the same name as the crate which
should be less confusing.

---------

Signed-off-by: Cyrill Leutwiler <bigcyrill@hotmail.com>

crates/resolc/src/const.rs

@@ -0,0 +1,16 @@
+//! Solidity to PolkaVM compiler constants.
+
+/// The default executable name.
+pub static DEFAULT_EXECUTABLE_NAME: &str = "resolc";
+
+/// The `keccak256` scratch space offset.
+pub const OFFSET_SCRATCH_SPACE: usize = 0;
+
+/// The memory pointer offset.
+pub const OFFSET_MEMORY_POINTER: usize = 2 * revive_common::BYTE_LENGTH_WORD;
+
+/// The empty slot offset.
+pub const OFFSET_EMPTY_SLOT: usize = 3 * revive_common::BYTE_LENGTH_WORD;
+
+/// The non-reserved memory offset.
+pub const OFFSET_NON_RESERVED: usize = 4 * revive_common::BYTE_LENGTH_WORD;