[EPIC] Works to do after entering ASF Incubating

[jerryshao]

Describe the proposal

There are many works we need to do after entering the ASF incubator, so here listed several things we should do recently:

Task list

• [Bug report] Some CI pipeline can't work after transfer Gravitino to Apache #4032
• [Improvement] Add the asf yaml for Gravitino #4031
• Update the license header to use Apache V2 license header instead of Company's one #4035
• Update the package name to use org.apache.gravitino #4036
• Update the README to claim an Apache incubating project and add an Incubating disclaimer #4048
• Update all the documents to refer to Apache Gravitino, not Gravitino or Datastrato Gravitino #4064
• Remove any unnecessary mention of Datastrato #4086
• Transfer the slack to Apache Gravitino Slack #4053
• Bootstrap the Apache Gravitino website #4071
• [Improvement] Update NOTICE files #4039
• [Minor] Update RAT check #4040
• Update documented security and governance policies to be in line with ASF policies #4073
• [Improvement] Replace code coverage tool Jacoco with codecov or something else  #4041
• [Subtask] Fix or update several broken CI workflows #4042
• Move to use ASF's DockerHub #4072
• Change footer link in webUI
• Update references to github.com/datastrato
• [Improvement] find a better way to check for license in .md files #4050
• Move documentation
• Move twitter? #4069
• Remove discourse
• Move/create YouTube
• Add Incubator DISCLAIMER #4074
• Submit logo to apache.org/logos
• Use new logo in the website
• Change docker user from datastrato to gravitino
• Change ranger download URL
• Update DockerHub URLs / docs
• Update Docs URL

[jerqi]

We should modify the license and document of playground, too.

[jerryshao]

We should modify the license and document of playground, too.

Yes, please also create issues to track this.