Mark transient transactions in DNF history

[evan-goode]

It may be useful to mark transient transactions as such in the DNF history database. dnf4 history list could display this marker in the table output or omit transient transactions by default. A flag could be added to history list to show only transient transactions.

dnf4 history list does include the command line used to initiate a transaction, which would include the --transient flag if it was used, but the user might have set persistence=transient in dnf.conf, so it's not clear whether the transaction was transient just based on the command line.

[ppisar]

What about moving the DNF history database under /usr which is subject of overlayfs?