re-drop CBOR index support & migration

[syphar]

This reverts commit 1912cad.

I ran find . | xargs -n 1 file | grep -v "directory" | grep -v "SQLite" in /opt/docs-rs-prefix/archive_cache with the results below.

All of them don't exist in the releases table, so they are remains of deleted releases / crates. I'll check if our deletion process is missing this piece in another PR. Some also did exist on crates.io, which will solved when I can finally run the consistency check.

So IMO we can proceed with dropping the CBOR support (again).

results

./rustdoc/primitive_enum/1.0.1.zip.index: data
./rustdoc/numX/0.2.0.zip.index: data
./rustdoc/num_x/0.2.2.zip.index: data
./rustdoc/pzem004t/0.1.1.zip.index: data
./rustdoc/vmadm/0.2.1.zip.index: data
./rustdoc/vmadm/0.2.0.zip.index: data
./rustdoc/vmadm/0.4.1.zip.index: data
./rustdoc/vmadm/0.3.0.zip.index: data
./rustdoc/armory_lib/0.3.10.zip.index: data
./rustdoc/armory_lib/0.3.4.zip.index: data
./rustdoc/armory_lib/0.3.11.zip.index: data
./rustdoc/armory_lib/0.3.3.zip.index: data
./rustdoc/armory_lib/0.3.5.zip.index: data
./rustdoc/armory_lib/0.3.2.zip.index: data
./rustdoc/castle_input_cursor/0.4.2.zip.index: data
./rustdoc/castle_input_cursor/0.4.1.zip.index: data
./rustdoc/castle_input_cursor/0.4.0.zip.index: data
./rustdoc/castle_input_cursor/0.3.2.zip.index: data
./rustdoc/gavle/0.1.0.zip.index: data
./rustdoc/docker-rust-api/1.42.1.zip.index: data
./rustdoc/docker-rust-api/1.42.0.zip.index: data
./sources/primitive_enum/1.0.1.zip.index: data
./sources/concurrency/0.1.2.zip.index: data
./sources/ciid/0.1.0.zip.index: data
./sources/ciid/0.2.0.zip.index: data
./sources/ciid/0.1.1.zip.index: data
./sources/numX/0.2.0.zip.index: data
./sources/num_x/0.2.2.zip.index: data
./sources/pzem004t/0.1.1.zip.index: data
./sources/vmadm/0.2.1.zip.index: data
./sources/vmadm/0.2.0.zip.index: data
./sources/vmadm/0.4.1.zip.index: data
./sources/vmadm/0.3.0.zip.index: data
./sources/armory_lib/0.3.10.zip.index: data
./sources/armory_lib/0.3.4.zip.index: data
./sources/armory_lib/0.3.11.zip.index: data
./sources/armory_lib/0.3.3.zip.index: data
./sources/armory_lib/0.3.5.zip.index: data
./sources/armory_lib/0.3.2.zip.index: data
./sources/castle_input_cursor/0.4.2.zip.index: data
./sources/castle_input_cursor/0.4.1.zip.index: data
./sources/castle_input_cursor/0.4.0.zip.index: data
./sources/castle_input_cursor/0.3.2.zip.index: data
./sources/gavle/0.1.0.zip.index: data
./sources/docker-rust-api/1.42.1.zip.index: data
./sources/docker-rust-api/1.42.0.zip.index: data
./sources/mat-clockwork-cli/5.4.0.zip.index: data

[syphar]

r? @Nemo157