Make e2e generic to work on old and new grafana version

[Flgado]

Run end-to-end tests against two Grafana versions in CI and ensure Grafana is fully ready before testing

Supersedes #321 and #303

[cla-bot]

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[cla-bot]

Thank you for your pull request and welcome to our community. We could not parse the GitHub identity of the following contributors: Jan Waś.
This is most likely caused by a git client misconfiguration; please make sure to:

1. check if your git client is configured with an email to sign commits git config --list | grep email
2. If not, set it up using git config --global user.email email@example.com
3. Make sure that the git commit email is configured in your GitHub account settings, see https://github.com/settings/emails

[cla-bot]

Thank you for your pull request and welcome to our community. We could not parse the GitHub identity of the following contributors: Jan Waś.
This is most likely caused by a git client misconfiguration; please make sure to:

1. check if your git client is configured with an email to sign commits git config --list | grep email
2. If not, set it up using git config --global user.email email@example.com
3. Make sure that the git commit email is configured in your GitHub account settings, see https://github.com/settings/emails

[cla-bot]

Thank you for your pull request and welcome to our community. We could not parse the GitHub identity of the following contributors: Jan Waś.
This is most likely caused by a git client misconfiguration; please make sure to:

1. check if your git client is configured with an email to sign commits git config --list | grep email
2. If not, set it up using git config --global user.email email@example.com
3. Make sure that the git commit email is configured in your GitHub account settings, see https://github.com/settings/emails

[cla-bot]

Thank you for your pull request and welcome to our community. We could not parse the GitHub identity of the following contributors: Jan Waś.
This is most likely caused by a git client misconfiguration; please make sure to:

1. check if your git client is configured with an email to sign commits git config --list | grep email
2. If not, set it up using git config --global user.email email@example.com
3. Make sure that the git commit email is configured in your GitHub account settings, see https://github.com/settings/emails

[Flgado]

@nineinchnick I think we may have a problem in the plugin. If you create a datasource A with token B, and then create another datasource but use token X, it will actually use token B, because we’re storing the token in a global variable. That happens on the e2e

[nineinchnick]

Yup, seems the issue is at

grafana-trino/pkg/trino/client/client.go

Line 17 in 7b190bc

token *Token

Looks like it's enough to move it into the client struct.

[Flgado]

yes @nineinchnick that should be enough. Will create a issue for that wdyt ?