Drop metapackage handling

[mtreinish]

While an original motivating feature for the development of the qiskit-bot release automation was to handle the metapackage sync between all the qiskit elements and automate as much of that process as we could. With the release of qiskit 0.44.1 the use of the metapackage has been official retired. Moving forward all qiskit releases are from a single repository and we don't need all the complex logic involved with bumping version numbers and requirements files anymore. While it's not a strong priority right now, we should drop all the metapackage functionality from qiskit-bot to simplify the code base.