Update Documentation and Contact Us pages

[rly]

Fix #59 and fix #60. And made the lottie animations on those pages smaller. Feel free to suggest changes.

[rly]

For Contact Us, I think pointing people to the GitHub issues page would be best instead of to the help desk or slack.

[CodyCBakerPhD]

For Contact Us

If you're sure - I personally see this as potentially becoming the new global entry point to the rest of the NWB ecosystem - but we can discuss that more at MIT and SFN

[CodyCBakerPhD]

For Contact Us, I think pointing people to the GitHub issues page would be best instead of to the help desk or slack.

Also, from prior experience, not every user is able to access a single communication channel seamlessly

There have been users on the DANDI side that were unable to open GitHub issue tickets due to being too new a user of the platform, or were false flagged by their bot detector, etc.

So it's useful to let people have multiple avenues to get in touch with problems

Can be enhanced in a follow-up