feat: 611 byo blessed samples

[t-fine]

Steps to test this new feature...

1. Create a samples.txt file that contains the gut hub URL to be cloned and published (this repo must contain a Makefile with a publish-only target):

root@zyber1:~/byo_test# cat samples.txt 
https://github.com/open-horizon-services/web-helloworld-python.git

2. Set the following environment variables:

export OH_EXAMPLES_REPO=https://raw.githubusercontent.com/t-fine/examples/refs/heads/feat_611_byo_blessed_samples
export BYO_SAMPLES=samples.txt

3. Run the AIO script:

curl -sSL https://raw.githubusercontent.com/open-horizon/devops/master/mgmt-hub/deploy-mgmt-hub.sh | bash

[t-fine]

Okay I think this is officially ready for review!

Some things to note: this will now only publish the custom set of samples if the text file is provided. There is an inconsistency with how the HZN_ORG_ID is set in the open-horizon/examples so I can't publish both at this moment

[joewxboy]

Looks good and functions as expected. Would like to see one or two example blessedSamples.txt files.

[t-fine]

Thanks for the review @joewxboy I'm going to go ahead and get this merged