Added tests for `confirm_email` action.

unless requested by admin or moderator.

for registration, authentication, email confirmation, confirmation resending.
Made admin methods create confirmed users.

Introduced User.register/1 to encapsulate User record creation and post-registration actions.

[#114] Account confirmation email, registration as unconfirmed (config-based), auth prevention for unconfirmed.

Instance/Runtime static plug

See merge request !567

This allows to set-up an arbitrary directory which overrides most of the
static files: index.html static/ emoji/ packs/ sounds/ images/ instance/
favicon.png.

If the files are not present in the directory, the bundled ones in
priv/static will be used.

2018 12 17 update frontend

See merge request pleroma/pleroma!565

Fix uploads test.

See merge request !564

Fix update_profile failing due to OAuth token record in assigns instead of string

Closes #459

See merge request !561

[#449] fix text field

See merge request pleroma/pleroma!563

Captcha

See merge request pleroma/pleroma!550

Fix tagging problems for existing instances.

See merge request !562

Add tests for Mix tasks

See merge request pleroma/pleroma!555

Upgrade to Phoenix 1.4

Closes #451

See merge request !560

WebFinger: Sends a 400 when resource param is missing, fix XRD typo in test

See merge request pleroma/pleroma!554