Fixes INFRA-197

The interface name shall start with the hostname of the host it is
associated to.

Note that this is only enforced via the UI (from which most users will interact),
not from the API.

Fixes INFRA-195

- add domain_id on NetworkScope table to define a default domain
- add domain_id on Network (default to the Network Scope one)

Fixes INFRA-194

We don't want to submit the form when scanning a code bar or ICS id.
In keyboard mode, the scanner sends a CR as last character.

Allow to use a scanner configured as keyboard to register items
via the web UI.
1. The attributes should be selected manually
2. Focus set manually on ICS id
3. Scan an ICS id -> prefix removed and focus set to serial number
4. Scan serial number
5. Click on submit
6. Focus set automatically on ICS id
7. Repeat from 3

Allow to keep track of batches of small parts.

Sorting on manufacturer/model/location/status requires
a join which removes the row with empty field.
Disable it until we find a way to sort properly including null values.

When there are more than a 1000 items in the table, retrieving and
displaying all items takes about 7 seconds.
This is every time we refresh the items page, which is too slow.

Column not visible but searchable.
Allow to search comments and TAG number for items imported from JIRA.

See https://github.com/showdownjs/showdown/wiki/Extensions

Allow to scan a label to enter an ICS id via the web interface

text is really generic and could conflict with another variable.
body is often used for comments.

Allow to customize the default selected values:
- the default network prefix can be defined in the configuration (default to 24)
- the default first and last IP chosen can probably be improved
  it defaults to hosts[9] and hosts[-5] if the list has more than 15
  elements or the first and last otherwise

Note that when using a small prefix (< 19), the number of possilbe IPs is quite
large and updating the first and last IP select field takes some time...

Scroll up to ensure the from input is not hidden below the navbar.

See https://github.com/twbs/bootstrap/issues/1768

Rendering done client side using Showdown: http://showdownjs.com
Live preview is shown below the form.
Only raw text is saved in the database (no HTML).

Note that no XSS filtering is done!
See https://github.com/showdownjs/showdown/wiki/Markdown's-XSS-Vulnerability-(and-how-to-mitigate-it)

Markdown to HTML converter in Javascript

Use endpoint argument to avoid collision with flask-admin Network

- disable item field for virtual hosts
- pre-fill interface name with hostname

- Main blueprint used to declare custom views for all blueprints.
(keep inventory blueprint cleaner)
- Add url_prefix to each blueprint

- All created tokens are stored in the database.
  To revoke a token, we just delete it from the database.
  Tokens not found in the database are thus considered unvalid / revoked.

- Add button to copy generated token to the clipboard

- Redesign profile page

See https://clipboardjs.com

This can be done via the Admin interface but this latter shall be
restricted to admin users. This simple page allows the group "create"
to easily add new Manufacturer, Model or Location.

- update flask-bootstrap
- update datatables to v1.10.15 for bootstrap 4 support