Part 4 of the migration. Final moves.

Previous PR: https://github.com/actualbudget/actual/pull/1420

Part 3 of the migration.

Part 2 here: https://github.com/actualbudget/actual/pull/1419

This cleans up all of the usage of `<a>` in the codebase. Now all
external links get the appropriate attributes added.

Depends on https://github.com/actualbudget/docs/pull/202.

Seems to build fine, will test later.

* Allow the server to auto-configure the server URL for the client

* Extract server URL/version logic out to ensure consistent updates

* ()

* Be more explicit about when the server version is re-fetched

* Use a single layer of context provider

* Move the bootstrap route to /account/needs-bootstrap

* No more `isActual`

* Refactor to call subscribe-needs-bootstrap instead of fetch()

* Dedupe calls to subscribe-needs-bootstrap

* Don’t revalidate the server when we just validated it

* simplify

* Fix setServerURL

*   upgrade eslint-plugin-import and fix issues

* Change import ordering

* Make ButtonSetting more generic

* Add an “Experimental Features” section in the settings

* Fix text color

* Put experimental features behind another link

* Update Encryption.js

* Update FixSplits.js

* Remove unused variable

* That’s what I get for coding on my phone

Co-authored-by: Matiss Janis Aboltins <matiss@mja.lv>

* Split the Settings component into multiple files (#434)
* Remove need for isMobile in CSS: lean on media queries in styles.js and glamor

Co-authored-by: Matiss Janis Aboltins <matiss@mja.lv>
Co-authored-by: Jed Fox <git@jedfox.com>