Use g_date_time_format() instead of g_date_time_format_iso8601() to only
rely on glib 2.56.0 which is the latest version in Debian Buster
(current stable).
We also only use basic sqlite functions so 3.27.0 should be fine there
(also the one in Debian buster).
Thanks to @DebXWoody.
We now dont get the log files from the text files via chat_log_get_previous() anymore.
We use the sql backend via log_database_get_previous_chat().
So far it just has the same behaviour like chat_log_get_previous(),
except that in _chatwin_history() we don't pass the sender to
win_print_history() which should be fixed in a commit soon.
And log_database_get_previous_chat() can later easily be expanded to fix
https://github.com/profanity-im/profanity/issues/205.
Maybe if we only use `/connect` we dont have ProfAccount. In that case
we won't log anything. Only if a account is used we log.
If this is the case or the init of the db didn't work we still want
profanity to run but wont log anything to the db.
I plan to save all messages in an SQLite db.
For retrieving information it's nicer than having it in a text file.
We will have more info in there and easier to parse it.
This will also be good for later MAM
(https://github.com/profanity-im/profanity/issues/660).
Regular text files will still be an option for users so that they can
easily grep them and do whatever they like.
Internally Profanity will only use the SQLite db.
