Unify file naming #5140
Description
According to https://typespec.io/docs/handbook/style-guide/. The file name should change to kebab case. Therefore, resource file name should follow. For some special cases:
VNetXxxx -> vnet-xxxxx
GZipXxxx -> gzip-xxxxx
IPv4Xxx -> ipv4-xxxxx
Otherwise,
VMMSScaleSet -> vmms-scale-set