Ref T613

This adds a new `landing` value in the [app] section of config.ini.
If non-empty, unauthenticated users on multi-user instances will be
redirected to the path given there.

This closes T574

Now the func takes a username and password instead of a single string.

This exposes setup and admin functions in the writefreely package, and
uses them in the main application, initialized by the flag parsing that
now happens there.

This is the first step towards making `writefreely` usable as a
standalone package.

Added /bin/lessc path to be compatible with CentOS 7

Tweak Makefile for MacOS

Fix the build in Docker after enabling go modules

Enabling go modules requires that GO111MODULE is set, so
we set it as an environment variable in the Dockerfile.

Also, go-bindata is meant to be installed globally, so we
force the install before enabling Go modules. Also, we update
Go to 1.12 to fix a couple module builds.

This also moves development instructions to documentation repo.

This makes it so we can keep all schema changes in the `migrations`
module, instead of adding them there *and* in the schema files. It
fixes #92 and should prevent these kinds of issues in the future.

Previously it referenced an image on write.as and had the incorrect
og:url property. This also fixes the canonical URL on single-user
instances. Closes #91

This reverts commit 5e7da6678d.

There are better standards in progress like a `capabilities` object:
https://litepub.social/litepub/lice.html

This indicates whether or not invites are enabled on this instance. It
requires an upgrade to writefreely/go-nodeinfo v1.2.0

Now admins can choose a title for their About and Privacy pages; now
editable through the instance page editor.

This adds `title` and `content_type` fields to the `appcontent` table,
requiring a migration by running `writefreely --migrate`

The content_type field specifies that items we're currently storing in
this table are all "page"s; queries for fetching these have been updated
to filter for this type. In the future, this field will be used to
indicate when an item is a stylesheet (ref T563) or other supported
type.

Ref T566

Support new commentsEnabled property

This adds a "Pages" section to the admin part of the site, and enables
admins to edit the pre-defined About and Privacy pages there, instead of
on the dashboard itself.

It also restructures how these pages get sent around in the backend and
lays the groundwork for dynamically adding static pages. The backend
changes were made with more customization in mind, such as an
instance-wide custom stylesheet (T563).

Ref T566

Using xgo comes with its own gomod-related issues. So let's see if this
fixes the build issue mentioned in the previous commit.

This will hopefully fix Travis errors:

/home/travis/.gimme/versions/go1.11.7.linux.amd64/pkg/tool/linux_amd64/link: running gcc failed: exit status 1
/usr/bin/ld: /tmp/go-link-810454258/000020.o: unrecognized relocation (0x2a) in section `.text'
/usr/bin/ld: final link failed: Bad value

This fixes an error: undefined: Asset

Based on @sheenobu's work on #58

Previously, moving an anonymous post to a blog would instantly federate
the post, regardless of its `created` date. This now respects that value
and doesn't federate the post if its `created` date is in the future.

This is the first part of supporting scheduled, federated posts (ref T567)
but technically fixes #76.

This is a field previously supported by PeerTube, and just recently
added on PixelFed, that should inform other ActivityPub services whether
or not comments are enabled on any given post. WriteFreely doesn't
support comments today, so this will always be false.

Add touch icons

(instead of the Write.as "w")

This removes HTML, in addition to the Markdown stripping that was
already happening.

This fixes #83

Resolve an edge case where last language has error

Previously, this check would only work if there was a pages/ dir in the
current working directory. Now it respects the pages_parent_dir
configuration setting.

If there are multiple language blocks on a page, we set the
onload on the last one to load all highlighting at once.

If the last language block has an error, the onload would
never fire and thus all blocks would not be highlighted.

The simplest resolution is to fire the callback regardless. We've
already loaded everything so running the callback is not causing any
performance hit which is relevant I think.

Previously when looking up an invite ID that doesn't exist, the database
call wouldn't communicate its non-existence in a standard way --
returning a nil object and nil error. Now the database call returns a
404 error, so handlers can show the correct page.

"zip" doesn't really describe what the posts themselves are exported as.
"txt" does.

These were missing.

and remove IRC link