Add two new severities
For altera-struct-pack-align, I reused the same severity as:
"optin.performance.Padding":                                  "LOW",
"alpha.unix.PthreadLock": "HIGH",
"alpha.unix.SimpleStream": "MEDIUM",
"alpha.unix.Stream": "MEDIUM",
+ "altera-struct-pack-align": "LOW",
"android-cloexec-creat": "MEDIUM",
"android-cloexec-fopen": "MEDIUM",
"android-cloexec-open": "MEDIUM",
"bugprone-narrowing-conversions": "MEDIUM",
"bugprone-not-null-terminated-result": "MEDIUM",
"bugprone-parent-virtual-call": "MEDIUM",
+ "bugprone-redundant-branch-condition": "LOW",
"bugprone-reserved-identifier": "LOW",
"bugprone-signed-char-misuse": "MEDIUM",
"bugprone-sizeof-container": "HIGH",
