[Computer Vision] Create CV API v3.0-preview (Azure#7402)

* [Computer Vision] Add Computer Vision v3.0 base config

* [Computer Vision] Add OCR v3.0 API changes

* Swap Analyze Post response back to 202

* Update version number to preview and revert location to Operation-Location

* Minor corrections after review with Paul

* Update Read API POST/Get and make Read language parameter optional

* Update CV base path to v3.0-preview

Update comment to re-trigger a build

* Remove all but OCR APIs in 3.0-preview

* Make Page level language tag optional

* Fix code style

* update path of ocr swagger to v3.0-preview and add date format

Co-authored-by: bob <bob@bob.com>