scripts: add oe-go-mod-fetcher for Go module VCS resolution

Add the oe-go-mod-fetcher.py tool and supporting files for resolving
Go module dependencies via git repositories instead of module proxies.

oe-go-mod-fetcher.py:
  - Parses go.mod and go.sum to identify required modules
  - Resolves module paths to git repositories (handles vanity URLs)
  - Maps module versions to git commits
  - Generates SRC_URI entries for bitbake fetcher
  - Creates go-mod-git.inc and go-mod-cache.inc files
  - Supports monorepo detection and nested module handling
  - Caches resolution results for performance

extract-discovered-modules.py:
  - Helper script to extract module information from discovery cache
  - Used by go-mod-discovery.bbclass during build

Also adds .gitignore to exclude runtime caches from version control.

Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/scripts/data/manual-overrides.json b/scripts/data/manual-overrides.json
new file mode 100644
index 00000000..5657c40c
--- /dev/null
+++ b/scripts/data/manual-overrides.json
@@ -0,0 +1,8 @@
+{
+  "_comment": "Git-tracked repository overrides for modules where automatic discovery fails.",
+  "_format": "module/path or module/path@version -> repository URL",
+  "_example": {
+    "example.com/broken-vanity": "https://github.com/org/actual-repo",
+    "example.com/versioned@v1.2.3": "https://github.com/org/specific-version-repo"
+  }
+}