Add option to verify patching without executing daemon.

[labkode]

Fixes #362

Example:

docker buildx build --build-arg TAG=36.0.0 --file ./daemons/Dockerfile  daemons/ --tag myrucio

Applies patches if any and starts daemon

docker run -e RUCIO_DAEMON=hermes myrucio
$ docker run -e RUCIO_DAEMON=hermes myrucio
=================== installing davix with openssl 3.1 ============================
rucio.cfg not found. will generate one.
INFO:root:Merged 74 configuration values from /tmp/rucio.config.default.cfg
INFO:root:Merged 0 configuration values from ENV
INFO:root:Writing /opt/rucio/etc/rucio.cfg
Patches not found
starting sendmail for hermes
....
....

Only applies patches:

$ docker run -e RUCIO_DAEMON_ONLY_CHECK_PATCHES=1 myrucio
=================== installing davix with openssl 3.1 ============================
rucio.cfg not found. will generate one.
INFO:root:Merged 74 configuration values from /tmp/rucio.config.default.cfg
INFO:root:Merged 0 configuration values from ENV
INFO:root:Writing /opt/rucio/etc/rucio.cfg
Patches not found
$ echo $?
0

[bari12]

@labkode did you discuss this with @ericvaandering yet? I will change the PR to draft in the meanwhile.

[labkode]

@bari12 yes all good. This PR does not have any impact in any deployment as it only adds an optional step.
However, after discussing with @ericvaandering I will add a few more improvements he suggested.