This change consolidates gtech_tool into registry_tool. Since App Engine has
no actual ACLs on the remote API (any access is essentially root access), we're
removing this to avoid giving the impression to users that gtech_tool is truly
locked down from a security perspective compared to registry_tool.
In addition to merging GtechTool.COMMAND_MAP into RegistryTool.COMMAND_MAP, this
change also removes the {create,update}_sandbox_tld commands (which only made
sense for gtech_tool) and removes references to gtech_tool in the documentation.
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=134828710
ee13ee35b0