Consider merging "forms" and "guides" into a unified list

[kydecker]

Currently we have two mostly-parallel content structures in Namesake:

1. Guides (step-by-step instructions for how to update your name in a particular place)
2. Forms (guided form-filling which results in a PDF you can download and present to a court or government official)

This split makes some amount of sense from a content architecture perspective (form content is stored in code; guide content comes from the CMS). But from a user perspective, it can be confusing.

For example, to understand how to file a court order in Massachusetts, the current "optimal" flow is:

1. Navigate to https://namesake.fyi/guides
2. (Optional) Read the getting started guide
3. Go back to /guides
4. Read the Court Order: Massachusetts guide
5. Click the "fill out forms" link, which takes you to the Court Order: Massachusetts form
6. Complete and download the form
7. Navigate back to the Court Order: Massachusetts guide and read the rest of the steps that explain what to do after your download

We should consider potentially merging these two areas of the site into one unified list of "places to change your name" which include a) the step-by-step "guide" content, b) any associated forms.

Ideally we should be able to do this while:

• Maintaining CMS control of step-by-step guide content
• Maintaining code control of forms
• Presenting a single unified experience to users

If we do end up unifying any of this structure, we should also make sure that existing URLs all have permanent 301 redirects to the new paths.

[kydecker]

After some discussion in Discord, the forms link will be removed from the site header and forms themselves will be embedded and usable inline from guides.

All existing routes are left intact, so users can still browse /forms and child routes for a full-screen experience.

See #556

The new "optimal" flow is now:

1. Navigate to https://namesake.fyi/guides
2. (Optional) Read the getting started guide
3. Go back to /guides
4. Read the Court Order: Massachusetts guide, completing the form inline

Will make additional improvements to the getting started flow in a future PR.