swupdate: bump to version 2018.03

swupdate: bump to version 2018.03

Remove upstream patches:
  * 0001-compat.h-introduce-compatibility-header.patch
  * 0002-Fix-build-if-DOWNLOAD-is-set-but-no-JSON.patch

Update note about bundled modified version of mongoose 6.11.

Update licenses. Some files are LGPL-2.1+ now. Remove Public Domain as the
relevant bundled sqlite3 code was removed some time age.

Regenerated the .config file by doing:

```
make swupdate-menuconfig
make swupdate-update-config
```
.. and removing the paths for the build options manually.

Signed-off-by: Jörg Krause <joerg.krause@embedded.rocks>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>