add features for license acceptance

[asadmg]

Description

Introduces the requirement for the user to explicitly accept the snowplow user license.

• A new boolean variable snowplow__license_accepted has been introduced in the dbt package's dbt_project.yml file.
• The default value of variable snowplow__license_accepted has been set to false.
• To use this dbt package, the user is required accept the Snowplow Personal and Academic License or have a commercial agreement with Snowplow. See: https://docs.snowplow.io/personal-and-academic-license-1.0.
• To accept, users should override the value of variable snowplow__license_accepted in their dbt project's dbt_project.yml by setting it to true.

What type of PR is this? (check all applicable)

• 🍕 Feature
• 🐛 Bug Fix
• 📝 Documentation Update
• 🎨 Style
• 🧑‍💻 Code Refactor
• 🔥 Performance Improvements
• ✅ Test
• 🤖 Build
• 🔁 CI
• 📦 Chore (Release)
• ⏩ Revert

Related Tickets & Documents

Checklist

• 🎉 I have verified that these changes work locally
• 💣 Is your change a breaking change?
• 📖 I have updated the CHANGELOG.md

Added tests?

• 👍 yes
• 🙅 no, because they aren't needed
• 🙋 no, because I need help

Added to documentation?

• 📓 internal package docs (ymls, macros, readme, if applicable)
• 📕 I have raised a Snowplow documentation PR if applicable (Link here if required)
• 🙅 no documentation needed

[optional] Are there any post-deployment tasks we need to perform?

[optional] What gif best describes this PR or how it makes you feel?