Configuration option to output logs in logfmt

[azuredream]

See more disscussion:
redis/redis#12934

Add ability to configure Redis to output logs in logfmt (See https://brandur.org/logfmt) as well as configure timestamp format options to more standard ISO 8601 or unix timestamp.

This change is implemented by two configs:
log-format: Either default or logfmt.
log-timestamp-format: default, iso8601, or unix.

#1006

$ ./valkey-server  /home/zhaoz12/git/valkey/valkey/valkey.conf
pid=109463 role=RDB/AOF timestamp="2024-09-10T20:37:25.738-04:00" level=warning message="WARNING Memory overcommit must be enabled! Without it, a background save or replication may fail under low memory condition. Being disabled, it can also cause failures without low memory condition, see https://github.com/jemalloc/jemalloc/issues/1328. To fix this issue add 'vm.overcommit_memory = 1' to /etc/sysctl.conf and then reboot or run the command 'sysctl vm.overcommit_memory=1' for this to take effect."
pid=109463 role=RDB/AOF timestamp="2024-09-10T20:37:25.738-04:00" level=notice message="oO0OoO0OoO0Oo Valkey is starting oO0OoO0OoO0Oo"
pid=109463 role=RDB/AOF timestamp="2024-09-10T20:37:25.738-04:00" level=notice message="Valkey version=255.255.255, bits=64, commit=affbea5d, modified=1, pid=109463, just started"
pid=109463 role=RDB/AOF timestamp="2024-09-10T20:37:25.738-04:00" level=notice message="Configuration loaded"
pid=109463 role=master timestamp="2024-09-10T20:37:25.738-04:00" level=notice message="monotonic clock: POSIX clock_gettime"
pid=109463 role=master timestamp="2024-09-10T20:37:25.739-04:00" level=warning message="Failed to write PID file: Permission denied"

[codecov]

Codecov Report

Attention: Patch coverage is 42.85714% with 20 lines in your changes missing coverage. Please review.

Project coverage is 70.57%. Comparing base (1b24168) to head (697ddfa).

Files with missing lines	Patch %	Lines
src/server.c	42.85%	20 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##           unstable    #1014      +/-   ##
============================================
+ Coverage     70.40%   70.57%   +0.17%     
============================================
  Files           114      114              
  Lines         61658    61688      +30     
============================================
+ Hits          43410    43537     +127     
+ Misses        18248    18151      -97     

Files with missing lines	Coverage Δ
src/config.c	78.69% <ø> (ø)
src/server.h	100.00% <ø> (ø)
src/server.c	88.07% <42.85%> (-0.53%)	⬇️

... and 13 files with indirect coverage changes