DRIVERS-2355 add crypt_shared download function to download-mongodb.sh

[kevinAlbs]

Summary

• Do not set MONGO_CRYPT_SHARED_DOWNLOAD_URL for versions < 6.0.
• Add download_and_extract_crypt_shared.

Background & Motivation

This intends to simplify using the same version of crypt_shared as the server for driver testing.
Queryable Encryption is still in Technical Preview and is subject to backwards breaking changes.
If backwards breaking changes are made, using different version of the server and crypt_shared may complicate diagnosing driver test failures.

Here is a POC of porting the Go driver scripts. This is the usage of the download_and_extract_crypt_shared:

. $DRIVERS_TOOLS/.evergreen/download-mongodb.sh
get_distro
get_mongodb_download_url_for "$DISTRO" "${VERSION}"
if [ -z "$MONGO_CRYPT_SHARED_DOWNLOAD_URL" ]; then
    echo "There is no crypt_shared library for distro='$DISTRO' and version='${VERSION}'".
    echo "SKIP_CRYPT_SHARED_LIB_DOWNLOAD: true" > expansion.yml
else
    echo "Downloading crypt_shared package from $MONGO_CRYPT_SHARED_DOWNLOAD_URL"
    download_and_extract_crypt_shared "$MONGO_CRYPT_SHARED_DOWNLOAD_URL" "$EXTRACT"
    touch expansion.yml
fi

[DmitryLukyanov]

LGTM