submit_report.sh, kdump.etc: Add log submission mechanism

Finally we have a functional mechanism to upload the crash logs
to Valve servers (special thanks to TonyP for the API help).
Documentation is present in the README.MD as usual.

NOTE: worth to reinforce here what was alread mentioned in the
README: kdump-steamos doesn't perform any significant validation
against malicious usage of the log submission mechanism, like DDoS,
submitting a malicious ZIP binary, a very huge file, etc.
All of this is expected to be handled by the server side.

Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>

PKGBUILD

@@ -7,7 +7,7 @@ pkgname=kdump-steamos
 pkgver=0.4
 pkgrel=1
 pkgdesc="Kdump scripts to collect vmcore/dmesg in a small dracut-based initramfs"
-depends=('dmidecode' 'dracut' 'kexec-tools' 'makedumpfile' 'systemd' 'zip' 'zstd')
+depends=('curl' 'dmidecode' 'dracut' 'jq' 'kexec-tools' 'makedumpfile' 'systemd' 'zip' 'zstd')
 arch=('x86_64')
 license=('GPL2')
 install=kdump-steamos.install
@@ -25,13 +25,13 @@ source=('20-kdump-steamos.conf'
 
 sha256sums=('dbedff54addfb5dce51614c73df04c90fca9f27d0d3a690243259ccbbfcca07c'
             '2514f79a496f76af847e262eadd55a5c2f8d95375cc513efa8cadd4cd98fe1d2'
-            'd0ac5e7e38fa1d3355eacdf70188483456f53d3e2b18cd161dea3df87b0b8f9c'
+            'fca89993e6ca76ec14f9a8e6761bec521903e2743ab9e05bfe2cd2b77e5e89f9'
             '8a556a9ebbda88dfd29b9620a0f2e7dbea19cd5fc019eb5dc4ebf7c80e4bf238'
             '06b38bd9f09da5fb22a765b6f1945fc349cc5f9d13cd32c9218b9b60b40a9010'
             '12a9124b907f208471ba7aaac0f3261cbbd34a168cce3260fa9e7793994beebd'
             '26bc2b64af0d468f050c0e0dd9e2053176d56886edad9146bc495797bf2c5810'
-            '0b602c27a5ff30c4fdb944135bbd9309225f31fb4ce354b7b07a03ce56b55531'
-            '8f974b51f6fcf5ec4ae8bb9d585390d4354cf8d99ae98e0efe9484f08abb1949'
+            '97d055f9e6e66cc4168767f5b51ff8e728c6935d270a997cf5b082ddd2d30634'
+            'b1a4a0f77cae137d3f5155a0fcc4b9d1e1b7ffd0089adb06b6bb21e71c751e27'
             'cbb207ecc0f6bacefbeed41f0d4910daac6500ac2345366e1f95f09a7653c65a')
 
 package() {