Separate compilation and linker phases (#376)

Separate between compilation and linker phases to allow deploy time
linking and back-porting era compiler changes to fix #91. Unlinked
contract binaries (caused by missing libraries or missing factory
dependencies in turn) are emitted as raw ELF object.

Few drive by fixes:
- #98
- A compiler panic on missing libraries definitions.
- Fixes some incosistent type forwarding in JSON output (empty string
vs. null object).
- Remove the unused fallback for size optimization setting.
- Remove the broken `--lvm-ir`  mode.
- CI workflow fixes.

---------

Signed-off-by: Cyrill Leutwiler <bigcyrill@hotmail.com>
Signed-off-by: xermicus <bigcyrill@hotmail.com>
Signed-off-by: xermicus <cyrill@parity.io>

crates/llvm-context/src/polkavm/context/debug_info.rs

@@ -2,6 +2,8 @@
 
 use std::cell::RefCell;
 
+use revive_common::BIT_LENGTH_WORD;
+
 use inkwell::debug_info::AsDIScope;
 use inkwell::debug_info::DIScope;
 
@@ -164,7 +166,7 @@ impl<'ctx> DebugInfo<'ctx> {
         &self,
         flags: Option<inkwell::debug_info::DIFlags>,
     ) -> anyhow::Result<inkwell::debug_info::DIBasicType<'ctx>> {
-        self.create_primitive_type(revive_common::BIT_LENGTH_WORD, flags)
+        self.create_primitive_type(BIT_LENGTH_WORD, flags)
     }
 
     /// Return the DIBuilder.