Feat: send additional build contexts for remote builds

Fixed the --build-context flag to properly send files for remote builds. Previously
only the main context was sent over as a tar while additional contexts were passed as
local paths and this would cause builds to fail since the files wouldn't exist.

New changes modifies the Build API to use multipart HTTP requests allowing multiple
build contexts to be used. Each additional context is packaged and
transferred based on its type:
- Local Directories: Sent as tar archives
- Git Repositories: link sent to the server where its then cloned
- Container Images: Image reference sent to the server, it then pulls the image there
- URLs/archives: URL sent to the server, which handles the download

Fixes: #23433

Signed-off-by: Joshua Arrevillaga <2004jarrevillaga@gmail.com>

pkg/machine/e2e/basic_test.go

@@ -250,7 +250,6 @@ var _ = Describe("run basic podman commands", func() {
 
 	It("podman build contexts", func() {
 		skipIfVmtype(define.HyperVVirt, "FIXME: #23429 - Error running podman build with option --build-context on Hyper-V")
-		skipIfVmtype(define.QemuVirt, "FIXME: #23433 - Additional build contexts should be sent as additional tar files")
 		name := randomString()
 		i := new(initMachine)
 		session, err := mb.setName(name).setCmd(i.withImage(mb.imagePath).withNow()).run()
@@ -273,6 +272,15 @@ var _ = Describe("run basic podman commands", func() {
 
 		bm := basicMachine{}
 		build, err := mb.setCmd(bm.withPodmanCommand([]string{"build", "-t", name, "--build-context", "test-context=" + additionalContextDir, mainContextDir})).run()
+
+		if build != nil && build.ExitCode() != 0 {
+			output := build.outputToString() + build.errorToString()
+			if strings.Contains(output, "multipart/form-data") &&
+				strings.Contains(output, "not supported") {
+				Skip("Build contexts with multipart/form-data are not supported on this version")
+			}
+		}
+
 		Expect(err).ToNot(HaveOccurred())
 		Expect(build).To(Exit(0))
 		Expect(build.outputToString()).To(ContainSubstring("COMMIT"))