Fix find_package(qasm <...>)

[vrpascuzzi]

We should have a coherent naming convention for the QASM library:
https://github.com/Qiskit/qss-compiler/blob/main/CMakeLists.txt#L43
and
https://github.ibm.com/IBM-Q-Software/qss-qasm/blob/master/CMakeLists.txt#L170-L180

I propose the following options:
(a) qss-compiler adheres to qss-qasm naming, i.e.,
find_package(qasm REQUIRED) -> find_package(OpenQASM REQUIRED); or
(b) qss-qasm adheres to qss-compiler, namely,
OpenQASMConfig.cmake -> qasmConfig.cmake
OpenQASMConfigVersion.cmake -> qasmConfigVersion.cmake

I'm, in a sense, torn between the options, but believe that we should go with (a), i.e., qss-compiler (and thusly Conan) conformance to qss-qasm conventions, esp. if qss-qasm will be open sourced.

In general, coherence is needed to prevent divergence between build envs/systems for all developers/users.

[taalexander]

Has this been resolved?