[DOCS]Improve videos page with tagging capability

[bhasudha]

Change Logs

Add UI changes to add tagging capability to videos page
Tag first few pages
Add Readme instructions on how to add video guides.

Impact

Website changes

Risk level (write none, low medium or high below)

Low Risk

Documentation Update

Describe any necessary documentation update if there is any new feature, config, or user-facing change

• The config description must be updated if new configs are added or the default value of the configs are changed
• Any new feature or user-facing change requires updating the Hudi website. Please create a Jira ticket, attach the
  ticket number here and follow the instruction to make
  changes to the website.

Contributor's checklist

• Read through contributor's guide
• Change Logs and Impact were stated clearly
• Adequate tests were added if applicable
• CI passed

[bhasudha]

Tested locally!

Note that the video tile images are not rendered in local testing. But should come up when published to site.