Bug Report: While testing Envbox following upgrade to Sysbox 0.6.5 on EC2 Instances issues with AL2023 crop up

## Summary

The Sysbox systemd unit files (sysbox-fs.service and sysbox-mgr.service) shipped with Sysbox 0.6.5 contain deprecated systemd configuration that causes issues on Amazon Linux 2023 (AL2023), preventing reliable Envbox deployments on EC2 instances.

Prior to this - the same scenario works with the Envbox with Sysbox 0.6.4 base.

## Environment

- **OS**: Amazon Linux 2023 (EC2 instances)
- **Sysbox Version**: 0.6.5
- **Use Case**: Supporting Envbox container runtime on AL2023

## Issues Identified

Following replication and troubleshooting, the log indicates sysbox-fs starts before sysbox-mgr, but no sysbox-fs.sock file is created, however in about half the starts, the sequence shows sysbox-mgr first following a successful sysbox-fs startup and a sysbox-fs.sock file.

Looking at this, shows issues with the systemd unit files for the two services.

### Deprecated `StartLimitInterval` Parameter

Since AL2023 uses systemd 252, the old parameters are of concern and the systemd unit files have not been updated for ~2 years.

Although not a deprecation issue, the other differences are versions of Systemd on AL2023, AL2 on 219, and going past 230 to 252 can lead to functionality changes. This may be a time-bomb for other OS systems if the upstream Systemd unit file is not fixed. Ubuntu:latest uses Systemd version 252 as well.

This issue is happening when Envbox is running on VM/Hardware/EC2 instances, which is counter to the aim of running on Kubernetes.

### Duplicate `Type=` Declarations
Both unit files contain:
```
Type=simple
Type=notify
```
This creates redundant declarations where only `Type=notify` should be used.

### Missing Service Dependencies and Ordering

Based on testing, the current configuration lacks proper service dependencies, leading to race conditions where sysbox-fs may start before sysbox-mgr is ready.

### Missing Restart Policies
No restart policies are defined, making the services less resilient to failures.

## Current Unit Files (Sysbox 0.6.5)

### sysbox-fs.service
```ini
[Unit]
Description=sysbox-fs (part of the Sysbox container runtime)
PartOf=sysbox.service
After=sysbox-mgr.service

[Service]
Type=simple
Type=notify
ExecStart=/usr/bin/sysbox-fs
TimeoutStartSec=10
TimeoutStopSec=10
StartLimitInterval=0
NotifyAccess=main
OOMScoreAdjust=-500
LimitNOFILE=infinity
LimitNPROC=infinity

[Install]
WantedBy=sysbox.service
```

### sysbox-mgr.service
```ini
[Unit]
Description=sysbox-mgr (part of the Sysbox container runtime)
PartOf=sysbox.service

[Service]
Type=simple
Type=notify
ExecStart=/usr/bin/sysbox-mgr
TimeoutStartSec=45
TimeoutStopSec=90
StartLimitInterval=0
NotifyAccess=main
OOMScoreAdjust=-500
LimitNOFILE=infinity
LimitNPROC=infinity

[Install]
WantedBy=sysbox.service
```

## Proposed Fix

This fix can be applied to the Envbox image directly, enabling users immediately.

### Simplified Patch Command
```bash
RUN sed -i \
-e '/^Type=simple$/d' \
-e 's/^StartLimitInterval=0$/StartLimitIntervalSec=0/' \
-e '/^\[Unit\]/a After=sysbox-fs.service\nRequires=sysbox-fs.service' \
/usr/lib/systemd/system/sysbox-mgr.service && \
sed -i \
-e '/^Type=simple$/d' \
-e 's/^StartLimitInterval=0$/StartLimitIntervalSec=0/' \
-e '/^\[Unit\]/a Before=sysbox-mgr.service' \
-e '/^\[Service\]/a Restart=on-failure\nRestartSec=2s\nStartLimitBurst=5\nStartLimitIntervalSec=30' \
/usr/lib/systemd/system/sysbox-fs.service
```

### Expected Result After Patch

#### sysbox-fs.service
```ini
[Unit]
Before=sysbox-mgr.service
Description=sysbox-fs (part of the Sysbox container runtime)
PartOf=sysbox.service

[Service]
Restart=on-failure
RestartSec=2s
StartLimitBurst=5
StartLimitIntervalSec=30
Type=notify
ExecStart=/usr/bin/sysbox-fs
TimeoutStartSec=10
TimeoutStopSec=10
StartLimitIntervalSec=0
NotifyAccess=main
OOMScoreAdjust=-500
LimitNOFILE=infinity
LimitNPROC=infinity

[Install]
WantedBy=sysbox.service
```

#### sysbox-mgr.service
```ini
[Unit]
After=sysbox-fs.service
Requires=sysbox-fs.service
Description=sysbox-mgr (part of the Sysbox container runtime)
PartOf=sysbox.service

[Service]
Restart=on-failure
RestartSec=2s
StartLimitBurst=5
StartLimitIntervalSec=30
Type=notify
ExecStart=/usr/bin/sysbox-mgr
TimeoutStartSec=45
TimeoutStopSec=90
StartLimitIntervalSec=0
NotifyAccess=main
OOMScoreAdjust=-500
LimitNOFILE=infinity
LimitNPROC=infinity

[Install]
WantedBy=sysbox.service
```

## Alternative Timeout/StartLimit Values for Testing

For environments experiencing timing issues, consider these alternative configurations:

### Conservative (Slower but More Reliable)
```ini
# sysbox-fs.service [Service] section additions
RestartSec=5s
StartLimitBurst=3
StartLimitIntervalSec=60
TimeoutStartSec=20

# sysbox-mgr.service [Service] section additions
RestartSec=5s
StartLimitBurst=3
StartLimitIntervalSec=60
TimeoutStartSec=60
```

### Aggressive (Faster but Less Tolerant)
```ini
# sysbox-fs.service [Service] section additions
RestartSec=1s
StartLimitBurst=10
StartLimitIntervalSec=20
TimeoutStartSec=5

# sysbox-mgr.service [Service] section additions
RestartSec=1s
StartLimitBurst=10
StartLimitIntervalSec=20
TimeoutStartSec=30
```

## Impact

- **Without fix**: Unreliable Sysbox startup on AL2023, preventing consistent Envbox deployments
- **With fix**: Proper service ordering, restart policies, and AL2023 compatibility