Regenerated CS Computer Vision & Bumped Major Version

[sarangan12]

Based on request from @lmazuel, I have regenerated the Cognitive Services Computer Vision TS SDK in this PR. Command used to regenerated SDK:

autorest --reset && autorest --typescript --license-header=MICROSOFT_MIT_NO_VERSION --typescript-sdks-folder=/Users/saranganrajamanickam/Projects/azure-sdk-for-js [email protected]/[email protected] --package-version=7.0.0 https://raw.githubusercontent.com/Azure/azure-rest-api-specs/master/specification/cognitiveservices/data-plane/ComputerVision/readme.md

A few pointers to give context:

1. I have waited for the completion of this PR: [Cognitive Service Computer Vision] Create CV v3.0 API version swagger azure-rest-api-specs#8734 before regenerating.
2. Last time, this SDK was regenerated on Sep 11, 2019. At that time autorest.typescript version - 4.2.2 was used for regeneration. Now, I have used autorest.typescript version - 4.2.4
3. Before this generation, the SDK was using 2.1 version of the service. After this version, the service got 3.0-preview (which we did not release) and then 3.0 (which is generated in this PR). As you can see, there are several breaking changes in the code. So, I have bumped the version to 7.0.0(from 6.0.0)
4. The regeneration has removed the example changes in README.md and started using the old node auth. I have discarded those changes.

@lmazuel FYI
@ramya-rao-a Please review and approve.