Reimplement Bitbucket lister using new Lister API

The new lister has incremental and full listing capability. It can request the Bitbucket API in anonymous and HTTP basic authentication modes. Rate-limiting is not aggressive and is handled.

Related to #2955 (closed)

Test Plan

Covered: incremental and full modes, tasks, authentication Not covered: some exceptional cases (see below)

tox

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Migrated from D4843 (view on Phabricator)