fix(ble): Use the term "pairing" in the UI

See merge request !403

See merge request card10/firmware!402

User study: https://twitter.com/schne1der_/status/1310698476108476418

Assorted fixes/cleanups

See merge request !401

Use CSPRNG for BTLE

See merge request !400

I don't trust the TRNG/PRNG combo inside the binary blob.

See merge request !399

The linker should already catch this case and error out early but just
to be absolutely sure, add a second check here so we don't get an
unexpectedly large epicardium binary which would overlap into pycardium
storage.

Signed-off-by: Rahix <rahix@rahix.de>

Hawkmoth is not yet working with Spinx 3; issue a warning when detecting
a Sphinx 3 environment as the resulting docs will be broken.

Signed-off-by: Rahix <rahix@rahix.de>

The tr hack we used so far has been painful.  The amount of locale
environment variables we need to set is surely a telling sign of that ...

Replace this with objcopy which can do the same thing, but much easier
and without locale related side effects ;)

Signed-off-by: Rahix <rahix@rahix.de>

Disable these warnings as they don't really help in our case:

    In file included from ../epicardium/modules/config.c:8:
    ../epicardium/modules/config.c: In function 'trim':
    ../epicardium/modules/config.c:133:28: warning: array subscript has type 'char' [-Wchar-subscripts]
      133 |  while (*start && !isgraph(*start))
          |                            ^~~~~~
    ../epicardium/modules/config.c:138:27: warning: array subscript has type 'char' [-Wchar-subscripts]
      138 |   while (*end && !isgraph(*end))
          |                           ^~~~
    ../epicardium/modules/config.c: In function 'epic_config_get_string':
    ../epicardium/modules/config.c:335:26: warning: array subscript has type 'char' [-Wchar-subscripts]
      335 |  while (*end && !iscntrl(*end))
          |                          ^~~~
    ../epicardium/modules/config.c: In function 'epic_config_set_string':
    ../epicardium/modules/config.c:519:28: warning: array subscript has type 'char' [-Wchar-subscripts]
      519 |   while (*end && (!iscntrl(*end) || isblank(*end)))
          |

Signed-off-by: Rahix <rahix@rahix.de>

See merge request !394

fix(trng): Enable TRNG before every read

See merge request !398

The BLE stack disables the TRNG every time it access it...

Update SDK to 0.2.1-12

See merge request !397