dnfjson: remove single Depsolve function and command

Remove the single Depsolve function from the dnfjson package and the
depsolve command from the dnf-json tool.  The new ChainDepsolve
functions and chain-depsolve command can handle single depsolves in the
same way so there's no need to keep (and have to maintain) two versions
of very similar code.

The ChainDepsolve function (in Go) and chain-depsolve command (in
Python) have been renamed to plain Depsolve and depsolve respectively,
since they are now general purpose depsolve functions.

dnf-json

@@ -147,37 +147,7 @@ class Solver():
             "packages": packages
         }
 
-    def depsolve(self, package_spec, exclude_spec):
-        self.base.install_specs(package_spec, exclude_spec)
-        self.base.resolve()
-        dependencies = []
-        for tsi in self.base.transaction:
-            # Avoid using the install_set() helper, as it does not guarantee
-            # a stable order
-            if tsi.action not in dnf.transaction.FORWARD_ACTIONS:
-                continue
-            package = tsi.pkg
-
-            dependencies.append({
-                "name": package.name,
-                "epoch": package.epoch,
-                "version": package.version,
-                "release": package.release,
-                "arch": package.arch,
-                "repo_id": package.repoid,
-                "path": package.relativepath,
-                "remote_location": package.remote_location(),
-                "checksum": (
-                    f"{hawkey.chksum_name(package.chksum[0])}:"
-                    f"{package.chksum[1].hex()}"
-                )
-            })
-        return {
-            "checksums": self._repo_checksums(),
-            "dependencies": dependencies
-        }
-
-    def chain_depsolve(self, transactions):
+    def depsolve(self, transactions):
         last_transaction = []
 
         for idx, transaction in enumerate(transactions):
@@ -266,15 +236,8 @@ def solve(request, cache_dir):
                 result = solver.dump()
                 printe("dump success")
             elif command == "depsolve":
-                job = transactions[0]
-                result = solver.depsolve(
-                    job["package-specs"],
-                    job.get("exclude-specs", [])
-                )
+                result = solver.depsolve(transactions)
                 printe("depsolve success")
-            elif command == "chain-depsolve":
-                result = solver.chain_depsolve(transactions)
-                printe("chain-depsolve success")
 
         except dnf.exceptions.MarkingErrors as e:
             printe("error install_specs")
@@ -318,7 +281,7 @@ def respond(result):
 
 def validate_request(request):
     command = request.get("command")
-    valid_cmds = ("depsolve", "dump", "chain-depsolve")
+    valid_cmds = ("depsolve", "dump")
     if command not in valid_cmds:
         return {
             "kind": "InvalidRequest",