Training

[lhmarsden]

I have added links to some of my training materials to the training page. Let me know what you think!

This was discussed in #539

[lhmarsden]

I notice that I have been clumsy here and included the commits from other pull requests here too, so I will close the other pull requests:

Including a link to the Nansen Legacy template generator:
#577

AGU prize:
#576
Which address this issue:
#551

[erget]

Thanks @lhmarsden - I love this, especially the fact that from here on out we can put flash messages up very easily!

I actually quite liked having multiple PRs devoted to different topics but will merge this now. If I were doing it and had my handy command line to hand, I would have proceeded somewhat as follows (not so easy with the setup I have in Windows) if I'd put them all in the same PR by accident:

1. Make a new branch from main
2. Cherrypick topic x onto that branch
3. Push as new branch to repo, make pull request for x
4. Repeat for all topics

Which is a fast thing to do but depending on your tooling is a bit of a pain. I note this only for future reference; I think this PR is fine to go.