* Added global http client
* Added Do func for global http client
* Changed the code to use the global http client
* Fix http client in volume uploader
* Fixed pkg name
* Fixed http util funcs
* Fixed http client for bench_filer_upload
* Fixed http client for stress_filer_upload
* Fixed http client for filer_server_handlers_proxy
* Fixed http client for command_fs_merge_volumes
* Fixed http client for command_fs_merge_volumes and command_volume_fsck
* Fixed http client for s3api_server
* Added init global client for main funcs
* Rename global_client to client
* Changed:
- fixed NewHttpClient;
- added CheckIsHttpsClientEnabled func
- updated security.toml in scaffold
* Reduce the visibility of some functions in the util/http/client pkg
* Added the loadSecurityConfig function
* Use util.LoadSecurityConfiguration() in NewHttpClient func
* Added context for the MasterClient's methods to avoid endless loops
* Returned WithClient function. Added WithClientCustomGetMaster function
* Hid unused ctx arguments
* Using a common context for the KeepConnectedToMaster and WaitUntilConnected functions
* Changed the context termination check in the tryConnectToMaster function
* Added a child context to the tryConnectToMaster function
* Added a common context for KeepConnectedToMaster and WaitUntilConnected functions in benchmark
Originally there are only url(ip + port), and publicUrl. Because ip was
used to listen for http service, it has less flexibility and volume
server has to be accessed via publicUrl.
Recently we added ip.bind, for binding http service.
With this change, url can be used to connect to volume servers. And
publicUrl becomes a free style piece of url information, it does not
even need to be unique.