Now the script supports more flashing methods:
- JLink (with tockloader)
- OpenOCD (with tockloader)
- pyOCD
- Nordic DFU
- none (will produce an IntelHex file)

Also merged the contributions from:
- Yihui Xiong to support the Makerdiary USB dongle board
- Dennis Geurts to support Nordic DFU

Doc updated accordingly.

Imported 2 patches for Tock kernel:
- 06-add-set_vector_table_offset.patch (upstream tock/tock#1579)
- 07-nrf52-bootloader.patch (upstream tock/tock#1681)

Sync patches with upstream Tock.

Add patch for bidirectional USB endpoints to fix panics in case of cancellation.

Fix extraneous globbing in workflows

Remove patch

According to the rules at https://help.github.com/en/actions/reference/workflow-syntax-for-github-actions#patterns-to-match-file-paths

This permits to run without persistent storage. The benefit is that the board
doesn't implement a the syscall API in Tock. The disadvantage is that rebooting
the key will reset the storage.

Add feature to track allocations in libtock-rs

Make internal python linter happy.

It seems that our internal linter is stricter than what pylint does.
Fixing the python code to make both happy and tries to fix the gap by
modifying pylintrc configuration file

Fix cargo audit workflow

The env context is only available at the step level, not the job one so
we need to use the github context instead. But the head_ref will only be
populated if we run in a pull_request event. So until we find a better
solution, let's match on the repo URL.

Fix clippy warnings.

Because of libtock-rs we can't run clippy on our codebase. But it could
run at least on `build.rs`.

Run everything that Travis-CI is running as Github workflows

These tests take 10 min. Let's avoid running them when not needed.