* Refactor blob store classes to use interface
* update to make some methods non-pure virtual
* Complete IBlobStoreEndpoint interface refactoring
Move doRequest, connect, returnConnection, updateSecret, writeEntireFile,
listObjects, and deleteRecursively from S3BlobStoreEndpoint to the shared
IBlobStoreEndpoint base class. Introduce provider hook methods
(setRequestHeaders, normalizeResourceForRequest, simulateRequestFailure,
processRequestFailure, preRetryCheck, extractCredentialFields) so that
the request loop is provider-agnostic.
Rename s3_backup_test.sh to backup_restore_test.sh and update CMake
to reflect the provider-agnostic naming.
Fix double proxy absolute-form rewrite bug where both
S3BlobStoreEndpoint::normalizeResourceForRequest and the base doRequest
would prepend http://host:port for proxy connections.
Fix getResourceURL duplication by having S3's override delegate to the
base class for shared knob-params/extra-headers logic.
* resolve review comments
* remove gcs auto region block
* clang format
* Enable +x bit.
* clang tidy
Trevor Clinkenbeard