Use standard string instead of sql.NullString for `style_sheet`, `script`, and `signature`.

Addresses #820

This truncates long titles and descriptions to the maximum column length, so
we don't get errors back from MySQL.

Fixes #600

This finishes the work started in #766, ensuring that requests to
canonical URLs of blogs and posts (not just at their API endpoints)
respond correctly to `application/ld+json;...` requests.

Fully addresses issue #564

- Shows all fediverse followers and email subscribers
- Shows number of email subscribers on Stats page
- Links to Subscribers page from Stats page

Requires running `make ui` to regenerate stylesheet.

Ref T826

This allows setting a URL, and then renders a <link> element
in the head of the blog. It requires a database migration.

Ref T744

Ref T805

Ref T805

This returns ActivityStreams objects when the Accept header is
`application/ld+json; profile="https://www.w3.org/ns/activitystreams"`,
per the ActivityPub spec.

Fixes #564

A Bunch Tell is now Musing Studio.

Ref T874 T744

Ref T805

Ref T805

This adds beginning email subscription functionality, with only MySQL support,
Mailgun support, and incomplete support for private instances. It includes
database changes, so run:

    writefreely db migrate

to use this feature.

Ref T856

Ref T770

This internally converts the configured host name into its Punycode ASCII
representation, while showing users the correct Unicode domain name.

From the writeas org on GitHub.

Closes T492

This skips the silenced-user check.

Ref T820

* Implements PrevPageURL and NextPageURL
* This allows the collection-tag template to get proper urls for
  paginating using tags.

Mostly copied the logic for pagination from non tag collection

Some WriteFreely instances are completely private, and thus have no need for public-
oriented features like Web Monetization. Like federation, this gives admins control
over whether or not the feature is enabled for users.

Ref T773

Ref T773

Update getCollectionPage godoc and reduce logic and variable assignments

This supports a new `monetization_pointer` collection attribute.
When present, we include the `monetization` meta tag on all
collection pages.

This enables users to add a signature to all blog posts, and update it from a single location.

Requires database migration with: writefreely db migrate

Closes T582

Ref T661

This notifies the user that the remote user doesn't exist, instead of
showing a blank page.

Ref T627

- Export the func
- Remove commented-out code
- Use log, not fmt for debug messages
- Remove named return parameters
- Use standard var naming schemes
- Fix spacing in queries and remove unnecessary chars

Previously, any password-protected collection on a suspended account
would prompt visitors for a password, and *then* take them to the "not
found" page. This fixes that.

This fixes a panic from a nil user when calling u.IsSuspended().
Instead, this checks and calls IsSuspended() on `owner`.

This changes all variables and functions from using Suspend{ed} to using
Silence{d} as well as documentation, errors and logging.

Some of the work needed to have the backend match user-facing wording.

Ref T661

From u.Status == UserSuspended to u.IsSuspended()

Ref T661

- update error messages to be correct
- move suspended message into template and include for other pages
- check suspended status on all relevant pages and show message if
logged in user is suspended.
- fix possible nil pointer error
- remove changes to db schema files
- add version comment to migration
- add UserStatus type with UserActive and UserSuspended
- change database table to use status column instead of suspended
- update toggle suspended handler to be toggle status in prep for
possible future inclusion of further user statuses

(https://github.com/writeas/writefreely/pull/195)

there it updates the table to include the handle.

migrations WIP

intermediate page (WIP) that shows the user profile page url

this changes the helper IsJSON to take a request instead of a string,
allowing to check multiple headers. In this case both Content-Type and
Accept.

With the var there now, this makes the code a bit more readable.

Includes:

* AP Collection fetching via canonical URL
* AP Collection fetching via API
* AP Post fetching via canonical URL
* AP Post fetching via API

Ref T693

This renders all requests for that user's posts, collections and related
ActivityPub endpoints with 404 responses.

While suspended, users may not create or edit posts or collections.

User status is listed in the admin user page

Admin view of user details shows status and now has a button to activate
or suspend a user.

GetCollections and GetPublishableCollections now take a hostname
parameter to allow setting the collecion hostname.

All collections used in memory now have their hostname set.

this changes GetPinnedPosts to accept an includeFutre bool, which
returns future dated pinned posts when true.