This commit switches the tweedledum requirement from being optional to a
hard requirement for installing qiskit-terra. We rely on tweedledum to
synthesize phase oracles which is commonly used functionality and several
issues have been opened. This use of tweedledum will likely continue to
grow so we should just list it as a requirement moving forward.

We originally made it optional because the functionality depending on
tweedledum was isolated to just the classical function compiler which
wasn't widely used. There were also packaging issues in the past where
the available precompiled binaries for tweedledum didn't support all of
our supported environments, but those have been resolved. There is still
an issue for arm64 macOS binaries but Qiskit doesn't have wide support
for that yet (although there is a job for terra).

At the same time this commit cleans up the optional requirements list
so that aer is no longer listed there and we add an 'all' extra so that
people can have a simple entypoint to install all the optional extras at
once.

Fixes Qiskit#6333
Fixes Qiskit#1253

Co-authored-by: Bruno Schmitt <[email protected]>

Co-authored-by: Luciano Bello <[email protected]>