acra_rollback docs into wiki

[gene-eu-zz]

describe acra_rollback script

[gene-eu-zz]

(e.g. this one #12)

[gene-eu-zz]

don't forget about selective decryption (either via specific select or via making only some key available)

[Lagovas]

@gene-eu https://github.com/cossacklabs/acra/wiki/Acra-rollback - check please

[Lagovas]

don't forget about selective decryption (either via specific select or via making only some key available)
decryption fully depends on select query that user pass to utility. so they can choose what data util will decrypt by filtering via select query.

when wrote doc, i noticed that now acra_rollback doesn't decrypt injected acrastructs into another data. is it important for now or create task on a future?

[gene-eu-zz]

for the future

[Lagovas]

https://github.com/cossacklabs/acra/wiki/Acra-rollback - current doc
if injected acrastructs for the future, update milestone please if current state is ok for 0.75