patterns: Add RPM pattern

[k0tran]

First attempt at implementing RPM package file format in pattern language. Would like your review and critique.

File spec: http://ftp.rpm.org/max-rpm/s1-rpm-file-format-rpm-file-format.html

Would also note that I decided not to patternize LZMA archive which is in this file too. Firstly it is an RPM and it already has a lot of patterns. Secondly LZMA should be separate pattern

[k0tran]

Actually it not always LZMA + CPIO
There is tag payloadformat which states for example CPIO
There is tag payloadcompressor which states for example lzma or xz
There is also payloadflags which specify compress level
RPM Source

But it is package contents anyway so I would propose just labeling it as that

[WerWolv]

Thanks a lot! Looks good to me.
Could you also upload a test file so the CI can run tests on your pattern?