Add compression to automated call recording archival

The Call Recording Reports module has functionality to automatically archive prior months recordings. The output file from this activity is a .tar file, which is nice for general archival, but does not give any savings for disk utilization (assumed primary reason for wanting to have an archive function, other than ease of transfer).

Feature request is to also enable the compression of the .tar file. Primary suggestion would be to use gzip as it has ubiquitous support in decompression tools on all platforms. bzip2 would be another prime candidate.