remove profile songs (ref #470) (#499)

* removes profile songs (ref #470)

* Remove ffmpeg, remaining song subsystem

  - Remove references to User.song in userpage* templates
  - Generate migration to drop column
  - Remove ffmpeg dependency in Docker

* remove python 2 era __future__ import

---------

Co-authored-by: TLSM <duolsm@outlook.com>

migrations/versions/2023_02_08_22_04_15_ba8a214736eb_remove_users_song.py

@@ -0,0 +1,28 @@
+"""remove users.song
+
+Revision ID: ba8a214736eb
+Revises: 1f30a37b08a0
+Create Date: 2023-02-08 22:04:15.901498+00:00
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = 'ba8a214736eb'
+down_revision = '1f30a37b08a0'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_column('users', 'song')
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.add_column('users', sa.Column('song', sa.VARCHAR(length=50), autoincrement=False, nullable=True))
+    # ### end Alembic commands ###