Update markdown docs with new project name

[annafil]

Description

This updates all docs text to Apache Polaris (Incubating) as the first mention, and Polaris subsequently. Also updating files I've touched to use the ASF license instead of the Snowflake copyright.

This does NOT update logos and images, will work on that after we have a new logo.

Fixes #196

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist:

Please delete options that are not relevant.

• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules
• If adding new functionality, I have discussed my implementation with the community using the linked GitHub issue

[annafil]

@jbonofre or @snazy can I haz some 👀 on this PR? I'm in merge conflicts territory because y'all beat me to the license headers :D Unfortunately I can't resolve merge conflicts without write access 🙈

[jbonofre]

@annafil you can fix the conflict by rebasing and force push on your repo fork. That way you don't need write permission. I can help you.

[annafil]

🤦‍♀️ @jbonofre you're right that actually wasn't that hard! 😬

I've resolved merge conflicts and auto-generated the docs pages to ensure they pick up all the changes pulled in alongside my own.

@snazy and @jbonofre ready for review I think!

[jbonofre]

@annafil I often do a rebase -i to squash all commits in one and force push. I will review the PR. Thanks 😃

[annafil]

@annafil I often do a rebase -i to squash all commits in one and force push. I will review the PR. Thanks 😃

That makes sense! Would you like me to do that first?

Before the move, the repo was configured to squash commits upon merge. Perhaps we can try to set that up again to make it easier for new contributors?

[jbonofre]

@annafil no it's ok. We can squash on github at merge time. Thanks !

[annafil]

awesome :) thank you for the guidance!