Closes #44.

Add UI for text-based folder invite code entry

Closes #46

See merge request !37

add a job to run cabal build

See merge request !38

we should keep it working for when we eventually add a test suite...

The input is accepted from the magic-folder view when the "+" button is
clicked.  This could be replaced by or augmented with a QR code-scanning
interface later.

Handle the new route in the controller as well, just by rendering the code
into the page as text.

Locally mirror CDN ressources

Closes #28

See merge request !36

(License is the same as for the MDC CSS)

`curl https://unpkg.com/material-components-web@latest/dist/material-components-web.min.js`
-> Found. Redirecting to /material-components-web@14.0.0/dist/material-components-web.min.js

`curl -LO https://unpkg.com/material-components-web@latest/dist/material-components-web.min.js`

`curl -L https://github.com/googlefonts/roboto/raw/main/LICENSE -o roboto`

```
curl 'https://fonts.googleapis.com/css?family=Roboto:300,400,500' -H 'accept: text/css,*/*;q=0.1' -H 'user-agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/111.0.0.0 Safari/537.36' --compressed -O
grep -oP 'http.*?woff2' roboto.css  | xargs -n 1 curl -O
sed -i 's|https://fonts.gstatic.com/s/roboto/v30/||' roboto.css
```

... after noticing Chrome gets WOFF2 instead of TTF fonts, I
copied the curl commandos with the right user agent strings etc.
directly out of the Chrome Dev Tools network window (right-click
copy as cURL) and downloaded that.

`curl -LO https://github.com/google/material-design-icons/raw/master/LICENSE`

```
curl -LO https://fonts.gstatic.com/s/materialicons/v140/flUhRq6tzZclQEJ-Vdg-IuiaDsNZ.ttf
mv flUhRq6tzZclQEJ-Vdg-IuiaDsNZ.ttf material-icons.ttf
```

curl -LO 'https://fonts.googleapis.com/icon?family=Material+Icons'

Commands used:

Get the version with:
`curl 'https://unpkg.com/material-components-web@latest/dist/material-components-web.min.css'`
-> "Found. Redirecting to /material-components-web@14.0.0/dist/material-components-web.min.css"

Aha so this is version 14.0.0! Download:

`curl -LO 'https://unpkg.com/material-components-web@latest/dist/material-components-web.min.css'`

Add the license:

`curl -LO https://raw.githubusercontent.com/material-components/material-components-web/master/LICENSE`

Remove reflex-material library

Closes #37

See merge request !35

Implement MagicFolders list view

Closes #31

See merge request !34

... it looks kinda odd where it's at on my mobile.

... the magic-folder list UI design doesn't have any

Thanks Haddock!  Who told you to run at all?