From RSA1024 (v2) to v3 now.

Closes #29669

Signed-off-by: David Goulet <dgoulet@torproject.org>

Our minimum version is now 0.2.9.5-alpha.  Series 0.3.0, 0.3.1,
0.3.2, 0.3.3, and 0.3.4 are now rejected.

Also, extract this version-checking code into a new function, so we
can test it.

Closes ticket 31549.

Also reject 0.3.5.0 through 0.3.5.6-rc as unstable.

Split some protocol error handling out of
connection_control_process_inbuf().

This refactor reduces the size of a practracker exception.

Closes 31840.

Closes 31923.

The documentation for this function says that the smartlist can
contain NULLs, but the code only handled NULLs if they were at the
start of the list.

We didn't notice this for a long time, because when Tor is run
normally, the sequence of msg_id_t is densely packed, and so this
list (mapping msg_id_t to channel_id_t) contains no NULL elements.
We could only run into this bug:
  * when Tor was running in embedded mode, and starting more than once.
  * when Tor ran first with more pubsub messages enabled, and then
    later with fewer.
  * When the second run (the one with fewer enabled pubsub messages)
    had at least some messages enabled, and those messages were not
    the ones with numerically highest msg_id_t values.

Fixes bug 31898; bugfix on 47de9c7b
in 0.4.1.1-alpha.

This test does not currently pass, because of bug 31898.

Since we want to make this function slightly more visible for testing
purposes, it needs a better name.

There is a bad design choice in two of our configuration types,
where the empty string encodes a value that is not the same as the
default value.  This design choice, plus an implementation mistake,
meant that config_dup() did not preserve the value of routerset_t,
and thereby caused bug #31495.

This comment-only patch documents the two types with the problem,
and suggests that implementors try to avoid it in the future.

Closes ticket 31907.

And add a runtime test that checks for unknown domains and flags.

Fixes bug 31854; bugfix on 0.2.1.1-alpha.

And do static checks on those macro definitions.

Part of 31854.

Preparation for 31854.