… spaces for MULTI_ARG configs parsing

Currently redis-server looks for arguments that start with `--`,
and anything in between them is considered arguments for the config.
like: `src/redis-server --shutdown-on-sigint nosave force now --port 6380`

MULTI_ARG configs behave differently for CONFIG command, vs the command
line argument for redis-server.
i.e. CONFIG command takes one bulk string with spaces in it, while the
command line takes an argv array with multiple values.

In this PR, in config.c, if `argc > 1` we can take them as is,
and if the config is a `MULTI_ARG` and `argc == 1`, we will split it by spaces.

So both of these will be the same:
```
redis-server --shutdown-on-sigint nosave force now --port 6380
redis-server --shutdown-on-sigint "nosave force now" --port 6380
```

And for MULTI_ARG, now we will check that it has at least one arg,
we can return `wrong number of arguments` before `config->interface.set`.
```
old:
src/redis-server --shutdown-on-sigint
>>> 'shutdown-on-sigint'
argument(s) must be one of the following: default, save, nosave, now, force

new:
src/redis-server --shutdown-on-sigint
>>> 'shutdown-on-sigint'
wrong number of arguments
```

This is mentioned in redis#10594 (comment)

Co-authored-by: Oran Agra <[email protected]>

The SHUTDOWN command has various flags to change it's default behavior,
but in some cases establishing a connection to redis is complicated and it's easier
for the management software to use signals. however, so far the signals could only
trigger the default shutdown behavior.
Here we introduce the option to control shutdown arguments for SIGTERM and SIGINT.

New config options:
`shutdown-on-sigint [nosave | save] [now] [force]` 
`shutdown-on-sigterm [nosave | save] [now] [force]`

Implementation:
Support MULTI_ARG_CONFIG on createEnumConfig to support multiple enums to be applied as bit flags.

Co-authored-by: Oran Agra <[email protected]>