Update autocrypt keyring documentation.

Recommend setting $autocrypt_dir to your normal keyring directory if
you want to use your existing key.

Trying to copy it over leads to signature verification issues.  Even
if I reversed the order (which is much less clean), that would just
lead to missing key signature errors for Autocrypt messages instead.
Fix --with-sqlite3 test for autocrypt.

Since $with_sqlite3 can contain a path, we want to check if it is
"no", not that it isn't "yes".
Add $ssl_use_tlsv1_3 config variable, default set.
Add size display configuration variables.

Although it would be nice to "open this up" more, performance and
security/stability issues would arise.

Based on the thread in mutt-dev, I hope these vars will satisfy most
customization needs:
  $size_show_bytes
  $size_show_mb
  $size_show_fractions
  $size_units_on_left
Fix LibreSSL build.

Apparently LibreSSL doesn't implement SSL_has_pending(), even for
newer versions.
Update POTFILES.in.

The file was missing a few files with translation strings:
copy.c, imap/auth_oauth.c, and safe_asprintf.c.
Add checks for buffered OpenSSL or GnuTLS data when polling.

I don't believe this has had an actual effect, because Mutt doesn't
support renegotiation, and we are only polling immediately after
sending NOOP.

However, it looks like checking is technically the correct thing to do
to avoid polling waiting for data that is already buffered.
Mention base64 keydata being stored in the autocrypt database.
Move LIBAUTOCRYPT before MUTTLIBS to fix building issues.
Add autocrypt and sqlite3 to .gitlab-ci.yml.
Add L10N comment about autocrypt menu help line abbreviations.
Add a note about autocrypt first-run and macros.
Add autocrypt documentation about shared key and keyring strategies.
Minor autocrypt manual section updates.

Mention key selection during account creation and $autocrypt_reply for
controlling autocrypt mode setting during replies.
Enabled writing protected subject with autocrypt too.
Turn off macro processing during autocrypt initialization.

The muttrc can push events into the macro buffer, with the assumption
that mailbox will be opened next.  This will interfere with the
prompts uses during first run.  The only issue is that macros won't
work inside the folder browser, if invoked.
Allow nested setting of OPTIGNOREMACROEVENTS.

This will be needed for the first-run of autocrypt initialization.
The initialization involves a number of prompts, and can even use the
folder browser.  The browser could in turn connect to IMAP which might
invoke a certificate prompt, login prompt, etc.
Add $autocrypt_reply.

This allows turning off the force-autocrypt mode when replying to an
autocrypt email.
Automatically clear screen when popping the last menu.

This removes the need to manually clear the screen during pre-menu
operations, such as autocrypt first run initialization.
Add ability to create autocrypt account from an existing key.

This is useful when adding accounts, or for users who want to use an
existing key from the keyring during initial account creation.
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