Integer overflow when parsing prefixed integers from qpack

[Ruben2424]

Changes in this PR:

• solves test failure on 32-bit. #284 by applying patch from https://salsa.debian.org/rust-team/debcargo-conf/-/blob/master/src/h3/debian/patches/allow-decoding-large-numbers-on-32-bit.patch
• Adds 32bit CI so tests run also on 32bit
• Allows only 9 instead of 10 follow up bytes in a qpack prefix integer to prevent integer overflow

Overflow

previous to this PR the prefix_int MAX_POWER restricted to 10 * 7 (70) bits, which does not fit in an u64.
This PR restricts the MAX_POWER to 9 * 7 (63) bits. This still meets the requirement from the qpack spec of 62 bit:

QPACK implementations MUST be able to decode integers up to and including 62 bits long.

This means our implementation now rejects some values that would fit in u64.
Since the spec only requires 62 bit i chose this approach instead of adding more logic to the decoder.

[Ruben2424]

@seanmonstar had to change a few things to satisfy CI after your review. Some unrelated to the original change:

I moved the server_and_client_should_connect_successfully rust test which spawned processes to a script which the ci now runs directly. Idk what exactly caused this to fail, but now it works.