Documentation and guidelines for V1

[mrosvik]

### Tasks
- [ ] https://github.com/digdir/designsystemet/issues/625
- [ ] https://github.com/digdir/designsystemet/issues/506
- [ ] https://github.com/digdir/designsystemet/issues/1103
- [ ] https://github.com/digdir/designsystemet/issues/1480
- [ ] https://github.com/digdir/designsystemet/issues/65
- [ ] https://github.com/digdir/designsystemet/issues/51
- [ ] https://github.com/digdir/designsystemet/issues/573
- [ ] https://github.com/digdir/designsystemet/issues/64
- [ ] https://github.com/digdir/designsystemet/issues/1482
- [ ] https://github.com/digdir/designsystemet/issues/1319
- [ ] https://github.com/digdir/designsystemet/issues/1496
- [ ] https://github.com/digdir/designsystemet/issues/1483
- [ ] https://github.com/digdir/designsystemet/issues/1484
- [ ] https://github.com/digdir/designsystemet/issues/1486
- [ ] https://github.com/digdir/designsystemet/issues/1487
- [ ] https://github.com/digdir/designsystemet/issues/586
- [x] https://github.com/digdir/designsystemet/issues/1497
- [ ] https://github.com/digdir/designsystemet/issues/540
- [ ] https://github.com/digdir/designsystemet/issues/1489
- [ ] https://github.com/digdir/designsystemet/issues/523
- [ ] https://github.com/digdir/designsystemet/issues/1490
- [ ] https://github.com/digdir/designsystemet/issues/1054
- [ ] https://github.com/digdir/designsystemet/issues/645
- [ ] https://github.com/digdir/designsystemet/issues/1343
- [ ] https://github.com/digdir/designsystemet/issues/1491
- [ ] https://github.com/digdir/designsystemet/issues/490
- [ ] https://github.com/digdir/designsystemet/issues/1492
- [ ] https://github.com/digdir/designsystemet/issues/1493
- [ ] https://github.com/digdir/designsystemet/issues/806
- [ ] https://github.com/digdir/designsystemet/issues/1494
- [ ] https://github.com/digdir/designsystemet/issues/1495
- [ ] https://github.com/digdir/designsystemet/issues/2284