Databricks-cli

Changelog
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* Remove dependency to `tenacity`.
* Add retries with exponential backoff on `429` status code for all HTTP requests sent through `databricks_cli.sdk.ApiClient`.

Fixing bug with creation of databricks-backed secret scope

Changelog
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* Update `pipelines` command to reflect changes in the API (https://github.com/databricks/databricks-cli/pull/304, https://github.com/databricks/databricks-cli/pull/308, https://github.com/databricks/databricks-cli/pull/317, mukulmurthy, rgovind3, aakash-db)
* Add support for cluster policies (https://github.com/databricks/databricks-cli/pull/303, itaiw)
* Add `tokens` command to expose the tokens API (https://github.com/databricks/databricks-cli/pull/246, areese, andrewmchen)
* Add support for `--cluster-name` or `--cluster-id` to `clusters` commands (https://github.com/databricks/databricks-cli/pull/313, areese, andrewmchen)
* Add `pipelines` `run` and `stop` commands (https://github.com/databricks/databricks-cli/pull/323, calving-db)
* Add retries with exponential backoff on 429 HTTP responses received from the DBFS API (https://github.com/databricks/databricks-cli/pull/319, https://github.com/databricks/databricks-cli/pull/326, gotibhai, bogdanghita-db).
* Improve error message on JSON errors (https://github.com/databricks/databricks-cli/pull/320, aakash-db)
* Hide token on databricks configure input (https://github.com/databricks/databricks-cli/pull/312, areese)
* Upgrade linters for py36 build (https://github.com/databricks/databricks-cli/pull/307, andrewmchen)

Changelog
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* Add the `pipelines` command group for managing Delta Pipelines with the initial commands `deploy`, `delete`, `get`, and `reset` (https://github.com/databricks/databricks-cli/pull/300, arulajmani, mukulmurthy, and null-sleep)
* Require configparser only in python < 3.6 (287, acxz)
* Support writeStatus flag in resource configuration in stack API (290, xuanwang14)

Changelog
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* Fix issue https://github.com/databricks/databricks-cli/issues/264. Add `init_scripts` optional argument to `create_cluster` and `edit_cluster` (https://github.com/databricks/databricks-cli/pull/266, malthe)
* Add DBC format support to Workspace API (https://github.com/databricks/databricks-cli/pull/276, svar29)
* Improve developer experience and error handling: when deleting directory structures recursively using `rm -r`, the user is presented with the progress of the delete operation and a message once the data has been successfully deleted. The end-to-end improvement is pending a change in the behavior of the `2.0/dbfs/delete` endpoint to be released in Q2 2020. The endpoint will return 503 when the delete operation could not finish before the timeout of 45s. (https://github.com/databricks/databricks-cli/pull/280, https://github.com/databricks/databricks-cli/pull/283, bogdanghita-db)

Changelog
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* Extend Stack CLI to support HTML file format (263, lu-wang-dl)
* Display Azure KeyVault URL for AKV-backed secret scope (265, nkangdatabricks)