notifications: add link to the build config in the email report

[padovan]

It turns out that people want quick access to the config, so it is a good idea to add them to the notification.

See https://lore.kernel.org/kernelci/ad97d7c2-8f99-42b0-b6e9-4685bcd62eb1@infradead.org/T/#mffd89a6ad85f8136fc02af51afad2e343b7fca63 for the community feedback.

Essentially it will look like this:

# Builds where the incident occurred:
 
## cros://chromeos-6.6/x86_64/chromeos-amd-stoneyridge.flavour.config+lab-setup+x86-board+CONFIG_MODULE_COMPRESS=n+CONFIG_MODULE_COMPRESS_NONE=y on (x86_64):
- compiler: gcc-12
- config:  https://files.kernelci.org/kbuild-gcc-12-x86-chromeos-amd-68d6bd56aabea828fddae00b/.config
- dashboard: https://d.kernelci.org/build/maestro:68d6bd56aabea828fddae00b
 
## cros://chromeos-6.6/x86_64/chromeos-intel-pineview.flavour.config+lab-setup+x86-board+CONFIG_MODULE_COMPRESS=n+CONFIG_MODULE_COMPRESS_NONE=y on (x86_64):
- compiler: gcc-12
- config: https://files.kernelci.org/kbuild-gcc-12-x86-chromeos-amd-68d6bd56aabea828fddae00b/.config
- dashboard: https://d.kernelci.org/build/maestro:68d6bd59aabea828fddae00e