Move package management code out of subproc.py

package_manager/bpkg/exceptions.py

@@ -0,0 +1,11 @@
+class BpkgException(Exception):
+    """Superclass for all package manager exceptions"""
+
+class InstallException(BpkgException):
+    """Raised when there is an error during installation"""
+
+class DownloadException(BpkgException):
+    """Raised when there is an error downloading something"""
+
+class BadRepository(BpkgException):
+    """Raised when reading a repository results in an error"""