chore: apply rust analyzer/clippy suggestions

feat: implement rudimentary database entry autocompletion

feat: add value hints to Command arguments

chore: use keepass Group 'get' method for getting node from a path

chore: update keepass dependency to 0.6.6

fix: only autocomplete flags only for given cmd

feat: do not autocomplete already used cmd flags

feat: add simple command + cmd args completion

feat: add command to close opened database

feat: add command to open database in repl

feat: do not require file as cmdline arg, throw error only on commands which require opened db

feat: show totp code with other fields if -s flag is added to show command

refactor: extract totp generation into a function

feat: ask user for password from stdin if it wasn't provided in args

build: update dependencies