Let hypercorn listen directly to privileged ports if run as root

[dfangl]

Motivation

This is basically a continuation of #8948 and #9012.

We basically reintroduce hypercorn binding directly to the privileged ports, if run as root.

Additionally, we check the sys.net.ipv4.ip_unprivileged_port_start kernel parameter, to check the port start of unprivileged ports.

We will need to provide proper paths of error handling, to avoid #9012 again.

Changes

• Bind hypercorn to privileged ports if root
• Check the actual unprivileged port start instead of assuming 1024.

[coveralls]

coverage: 83.013% (-0.05%) from 83.064% when pulling fe55d81 on hypercorn-privileged-port-binding into 9ccb39c on master.

[github-actions]

LocalStack Community integration with Pro

       2 files  ±0         2 suites  ±0   1h 14m 4s ⏱️ + 3m 6s
2 220 tests ±0  1 723 ✔️ ±0  497 💤 ±0  0 ❌ ±0 
2 221 runs  ±0  1 723 ✔️ ±0  498 💤 ±0  0 ❌ ±0 

Results for commit fe55d81. ± Comparison against base commit 9ccb39c.

[thrau]

LGTM!