fix: ensure MetricDir is created with correct permissions (when umask is set)

[brainexe]

In our case, we have a "grafsy" user running with umask 0022.
When starting on a fresh system or restarting the VM (which also wipes /tmp), the service created /tmp/grafsy with 755 instead of 777.
In this case I'd suggest to force create the directory with the full 777 on grafsy level already.

Reproduction steps:

$ sudo service grafsy stop && sudo rm /tmp/grafsy -rf && sudo service grafsy restart && ls -lsa /tmp/grafsy
total 4
0 drwxr-xr-t  2 grafsy grafsy    6 Sep  2 11:54 .
4 drwxrwxrwt 15 root   root   4096 Sep  2 11:54 ..

With the change in config.go, its:

$ ls -lsa /tmp/grafsy
total 4
0 drwxrwxrwt  2 grafsy grafsy    6 Sep  2 11:56 .
4 drwxrwxrwt 14 root   root   4096 Sep  2 11:58 ..

• side fix: don't force go 1.23 toolchain

[Felixoid]

I'm afraid it looks like UNIX-specific things.

We need to take care of separating them into all these files:

[brainexe]

year, true, now doing it the more simple way (mkdir+chown)

[Felixoid]

LGTM, @leoleovich?

[leoleovich]

Looks good, usually we ask to squash commits into 1 but GitHub allows to do so while merging