update docker functionality

[aethrvmn]

This updates building nimforum using docker. Specifically it updates the Dockerfile to use 2.2.4-ubuntu-regular, and the entrypoint to use nim c instead of nimble c. Finally, it adds --mm:refc when building src/forum because ORC causes a segfault inside the docker.

[aethrvmn]

For reference, I couldn't get Dockerfile.alpine to work, having the exact same setup as above, for 2.2.4-alpine-regular I get

64.23         ... /root/.nimble/pkgs2/bcrypt-0.2.1-5d8719a26c03137b6c38dbf13e9a102b985f8d18/bcrypt/arc4random.c:26:10: fatal error: sys/cdefs.h: No such file or directory
64.23         ...    26 | #include <sys/cdefs.h>
64.23         ...       |          ^~~~~~~~~~~~~
64.23         ... compilation terminated.
64.23         ... /root/.nimble/pkgs2/bcrypt-0.2.1-5d8719a26c03137b6c38dbf13e9a102b985f8d18/bcrypt/blowfish.c:34:10: fatal error: sys/cdefs.h: No such file or directory
64.23         ...    34 | #include <sys/cdefs.h>
64.23         ...       |          ^~~~~~~~~~~~~
64.23         ... compilation terminated.
64.23         ... /root/.nimble/pkgs2/bcrypt-0.2.1-5d8719a26c03137b6c38dbf13e9a102b985f8d18/bcrypt/crypt-blowfish.c:31:10: fatal error: sys/cdefs.h: No such file or directory
64.23         ...    31 | #include <sys/cdefs.h>
64.23         ...       |          ^~~~~~~~~~~~~
64.23         ... compilation terminated.
64.23         ... Error: execution of an external compiler program 'gcc -c  -w -fmax-errors=3 -pthread -O3 -fno-strict-aliasing -fno-ident -fno-math-errno   -I/nim/lib -I/app/src -o /root/.cache/nim/forum_r/@m..@s..@[email protected]@[email protected]@[email protected] /root/.nimble/pkgs2/bcrypt-0.2.1-5d8719a26c03137b6c38dbf13e9a102b985f8d18/bcrypt/arc4random.c' failed with exit code: 1
64.23        Tip: 444 messages have been suppressed, use --verbose to show them.
64.23 nimble.nim(415)          buildFromDir
64.23 
64.23     Error:  Build failed for the package: nimforum
------
WARN[0000] current commit information was not captured by the build  error="failed to read current commit information with git rev-parse --is-inside-work-tree"
failed to solve: process "/bin/sh -c nimble install -Y" did not complete successfully: exit code: 1