Add page on how to back up & restore all partitions

[ZimbiX]

I know a full backup of all partitions can be made with MTKClient using mtk rl <dir>. This took about an hour for me, reading the 128 GB at ~35 MB/s (note that writing to your disk must be faster than this, or you'll run out of RAM and the process will probably be OOMKilled - as happened to me originally when trying to back up to a remote server on a 5 MB/s uplink). Afterwards, I gzip'd the massive mostly-empty userdata partition, which took it down from 112 GB to 36 GB.

I haven't tried restoring yet - that might actually simply be a matter of mtk wl <dir>.

Edit: Issue for speed problem: bkerler/mtkclient#710

[shymega]

Yes, this would be a good page to have.