[Characterization] Add room acoustics test statistics analysis scripts
Room acoustics testing is a part of IVAS characterization. The statistical analysis of the test results is proposed in [S4-251256](https://www.3gpp.org/ftp/tsg_sa/WG4_CODEC/TSGS4_133-e/Docs/S4-251256.zip). This task is about adding related scripts to the repository.
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