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/project/contract/ir/llvm_ir.rs

@@ -0,0 +1,21 @@
+//! The contract LLVM IR source code.
+
+use serde::Deserialize;
+use serde::Serialize;
+
+/// The contract LLVM IR source code.
+#[derive(Debug, Serialize, Deserialize, Clone)]
+#[allow(clippy::upper_case_acronyms)]
+pub struct LLVMIR {
+    /// The LLVM IR file path.
+    pub path: String,
+    /// The LLVM IR source code.
+    pub source: String,
+}
+
+impl LLVMIR {
+    /// A shortcut constructor.
+    pub fn new(path: String, source: String) -> Self {
+        Self { path, source }
+    }
+}