feat: add support for Mercurial (hg) source handling in mod.rs

- Implemented `split_hg_url` to parse Mercurial URLs and revisions.
- Added `checkout_hg` function to clone Mercurial repositories.
- Integrated Mercurial handling into the `prepare_one` function to support resuming builds.
- Added tests for `split_hg_url` to ensure correct parsing of URLs and revisions.

---

feat: introduce legacy STARBUILD conversion support in starbuild.rs

- Created `ConvertedStarbuild` and `ParsedStarbuild` structs to manage conversion data.
- Implemented `convert_starbuild_file` to parse STARBUILD files and generate package specifications.
- Added functions to handle parsing of various STARBUILD constructs, including dependencies and build phases.
- Developed a build script generator for STARBUILD, supporting custom install functions.
- Included tests to validate conversion of single and multi-output STARBUILD files.

Cargo.lock

@@ -418,7 +418,7 @@ checksum = "807800ff3288b621186fe0a8f3392c4652068257302709c24efd918c3dffcdc2"
 
 [[package]]
 name = "depot"
-version = "0.31.0"
+version = "0.31.1"
 dependencies = [
  "anyhow",
  "ar",
@@ -3090,9 +3090,9 @@ dependencies = [
 
 [[package]]
 name = "zip"
-version = "8.3.1"
+version = "8.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5c546feb4481b0fbafb4ef0d79b6204fc41c6f9884b1b73b1d73f82442fc0845"
+checksum = "7756d0206d058333667493c4014f545f4b9603c4330ccd6d9b3f86dcab59f7d9"
 dependencies = [
  "aes",
  "bzip2",