revive llvm builder utility (#154)

Pre-eliminary support for LLVM releases and resolc binary releases by streamlining the build process for all supported hosts platforms.

- Introduce the revive-llvm-builder crate with the revive-llvm builder utilty.
- Do not rely on the LLVM dependency in $PATH to decouple the system LLVM installation from the LLVM host dependency.
- Fix the emscripten build by decoupling the host and native LLVM dependencies. Thus allowing a single LLVM emscripten release that can be used on any host platform.
- An example Dockerfile building an alpine container with a fully statically linked resolc ELF binary.
- Remove the Debian builder utilities and workflow.

crates/llvm-builder/src/ccache_variant.rs

@@ -0,0 +1,31 @@
+//! Compiler cache variants.
+
+/// The list compiler cache variants to be used as constants.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub enum CcacheVariant {
+    /// Standard ccache.
+    Ccache,
+    /// Mozilla's sccache.
+    Sccache,
+}
+
+impl std::str::FromStr for CcacheVariant {
+    type Err = String;
+
+    fn from_str(value: &str) -> Result<Self, Self::Err> {
+        match value {
+            "ccache" => Ok(Self::Ccache),
+            "sccache" => Ok(Self::Sccache),
+            value => Err(format!("Unsupported ccache variant: `{}`", value)),
+        }
+    }
+}
+
+impl std::fmt::Display for CcacheVariant {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        match self {
+            Self::Ccache => write!(f, "ccache"),
+            Self::Sccache => write!(f, "sccache"),
+        }
+    }
+}