kiss-live v2.0 - diskless stage

[eudaldgr]

I'm not sure to merge this, so I create this PR.

Goal:

• [x] Make kiss-live the KISS way
• [x] Compress as much as possible
• [x] Simpler tinyramfs hook, maybe portable also
• [x] Simpler bootloader config
• [x] Less packages (19 for now, 3 less)
• [x] Better file system hierarchy
• [x] Reduce .iso file size (at this moment only ~84M - ~32.8% less since last release)
• [x] -binaries flag have sense now? no sense
• [x] All works? (boots at least)

Cons:

• [x] At least 500M of ram needed, I can live with that
• [x] Not "really" live, that's enough

P.S.: heavily inspired by alpine

[eudaldgr]

• last release: 125M manifest
• new diskless: ~84M manifest