v0.46.5: enable users to prepare the flutter engine within docker image withou…
…t building first. (#214)
* create prepare-engine subcommand and use it in the dockerfile
* fix(deps): github.com/otiai10/[email protected]: missing go.sum entry
* fix(deps): go mod tidy
* fix: swap engine prep to debug mode
* fix: add missing ~ to CGO_LDFLAGS
* remove support for multiple target OSes in prepare-engine.
remove the prepare step within the docker image, users can prepare which ever engines they need on the fly
add all supported engines to the CGO_LDFLAGS of the docker image
* FEAT: add profile mode
FIX: ensure exactly one mode is set at a time
* FIX: don't check for darling within prepare-engine, simply fail for darwin releases
* FIX: fail to prepare engine in release mode if on darwin
* FIX: add profile for windows and linux
* REQUEST: rework prepare mode validation logic
FEAT: debug mode is default again