Grafazos: customize dashboards uid

What

Grafazos: add an option to set a dashboard uid.

cf. discussion on https://tezos.slack.com/archives/C085TSMAD5F/p1742934485944939

Why

Grafazos currently does not set the grafana dashboard uid, which result in non-predictable value for the dashboard created. And since the dashboard uid is present in it's URL, it makes it non-predictable URL.

How

By default, dashboards are created without uid, resulting in a random one assigned by grafana. You can set a specific uid with the UID variable, which will be concatenated to a default uid set in each dasboard's definition.

If UID is set to the empty string, then the uid is set to the default uid value set for each dashboard.

Manually testing the MR

cd grafazos

make && cp -fr output output-default
UID="" make && cp -fr output output-uid-empty
UID="-mr17542" make && cp -fr output output-uid-set

diff -r output-default output-uid-empty
diff -r output-default output-uid-set

Click to expand

Clean output directories created for the tests

rm -fr output-default output-uid-empty output-uid-set

Checklist

• Document the interface of any function added or modified (see the coding guidelines)
• Document any change to the user interface, including configuration parameters (see node configuration)
• Provide automatic testing (see the testing guide).
• For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR