stop uploading packages to downloads.rapids.ai (#883)

Contributes to rapidsai/build-planning#181

* removes all uploads of conda packages and wheels to `downloads.rapids.ai`

## Notes for Reviewers

### How I identified changes

Looked for uses of the relevant `gha-tools` tools, as well as documentation about `downloads.rapids.ai`, being on the NVIDIA VPN, using S3, etc. like this:

```shell
git grep -i -E 's3|upload|downloads\.rapids|vpn'
```

### How I tested this

See "How I tested this" on rapidsai/shared-workflows#364

Authors:
  - James Lamb (https://github.com/jameslamb)

Approvers:
  - Bradley Dice (https://github.com/bdice)

URL: #883

Author: jameslamb

ci/build_cpp.sh

@@ -24,5 +24,3 @@ sccache --zero-stats
 RAPIDS_PACKAGE_VERSION=$(rapids-generate-version) rapids-conda-retry build conda/recipes/libcucim
 
 sccache --show-adv-stats
-
-rapids-upload-conda-to-s3 cpp

ci/build_python.sh

@@ -33,5 +33,3 @@ RAPIDS_PACKAGE_VERSION=$(head -1 ./VERSION) rapids-conda-retry build \
   conda/recipes/cucim
 
 sccache --show-adv-stats
-
-rapids-upload-conda-to-s3 python

ci/build_wheel.sh

@@ -14,8 +14,6 @@ source rapids-init-pip
 
 rapids-generate-version > ./VERSION
 
-RAPIDS_PY_CUDA_SUFFIX="$(rapids-wheel-ctk-name-gen "${RAPIDS_CUDA_VERSION}")"
-
 rapids-logger "Generating build requirements"
 
 rapids-dependency-file-generator \
@@ -62,5 +60,3 @@ python -m auditwheel repair -w "${RAPIDS_WHEEL_BLD_OUTPUT_DIR}" dist/*
 ls -1 "${RAPIDS_WHEEL_BLD_OUTPUT_DIR}" | grep -vqz 'none'
 
 ../../ci/validate_wheel.sh "${RAPIDS_WHEEL_BLD_OUTPUT_DIR}"
-
-RAPIDS_PY_WHEEL_NAME="${package_name}_${RAPIDS_PY_CUDA_SUFFIX}" rapids-upload-wheels-to-s3 python "${RAPIDS_WHEEL_BLD_OUTPUT_DIR}"