Hide admin button for users without admin access

There are several types of user with access to the review dashboard, but
only administrators are allowed to view the administrator pane.

This updates the admin dashboard to only render the admin button for
users with admin permission.  It also adds an ID to the button so
that test can reliably check for the presence of the button.

Issue #2724

Bump url-parse from 1.5.3 to 1.5.7

Bumps [url-parse](https://github.com/unshiftio/url-parse) from 1.5.3 to 1.5.7.
- [Release notes](https://github.com/unshiftio/url-parse/releases)
- [Commits](https://github.com/unshiftio/url-parse/compare/1.5.3...1.5.7

)

---
updated-dependencies:
- dependency-name: url-parse
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <support@github.com>

Environs env.url() returns a URL object so replace with env.str()

Use environs package to parse  .env variables.

Add collectstatic step to CI.

Bump follow-redirects from 1.14.7 to 1.14.8

The `AdminFactory` had a bug: `is_admin` is not a field, but
`is_superuser` is.

No tests were using the factory so this went unnoticed, but I'm about to
want to use it.

chore: gitignore .mo files

Bumps [follow-redirects](https://github.com/follow-redirects/follow-redirects) from 1.14.7 to 1.14.8.
- [Release notes](https://github.com/follow-redirects/follow-redirects/releases)
- [Commits](https://github.com/follow-redirects/follow-redirects/compare/v1.14.7...v1.14.8

)

---
updated-dependencies:
- dependency-name: follow-redirects
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <support@github.com>

Closes #2720

Add .editorconfig

Editorconfig is a standard that helps editors know what whitespace rules
to follow for a given project.

For more information, see:

https://editorconfig.org/

These rules were determined based on feedback from project maintainers.

There are some files that use different numbers of spaces, but these
files were imposed on the project externally.  We use 4 everywhere we
touch.

Issue #2716

Ensure errors are on top

In certain cases validation errors could be hidden by components that
were rendered "on top" (e.g. in the case of required rich text fields).

Providing a z-index signals that they belong on top.

Issue #2718

Add Finance flow fixes and notifications

Upgrade jest to latest version

Parse locale for currency lookup with dash separator

Correctly validate Slack field as optional

Closes #2714

Add Finance 1 and Finance 2 Flow