UI and tooltip clarifications

Hi Bradley, Shaun,

I have been doing some work to provide more clarification to users registering their (first and only) SP (or IdP) into the FR.

We have had a number of cases where the users misplaced the typically SP under a wrong organization - typically, because they could not find their organization and because they did not know they need to register one.  So they e.g. picked the name representing the core federation services (Tuakiri in our case) as their choice...

The changes I have made:
* add a tooltip to the Orgaization selection listbox on the IdP and SP create page
* optionally, also add additional hints above the Create Org/IdP/SP buttons on the landing page.  These are customizable from the branding and the default branding would provide blank values (with suitable commented-out values with actual hints), so no change to the layout if you just merge the code.
* optionally, also add an alert box on the IdP registration page warning against having multiple IdPs under the same Organization (breaks with DS implementation using the Organization name from the metadata).  Again, the text defaults to blank, meaning no UI change.
* and, I have also updated the tooltips for IdP Scope and eduPersonEntitlement values to indicate support for regexp syntax which we already have.

Please let me know whether you are happy to merge this or would want some of it further clarified.

Cheers,
Vlad

PS: You can see the actual rendering of the modified welcome page at https://registry.tamaki.dev.tuakiri.ac.nz/federationregistry/ (and actually, all of the above)