lint: generate options from kconfigcheck.toml

Now that we have moved the kconfigcheck configuration into pmaports branches via kconfigcheck.toml, it is time to get rid of the hardcoded list of valid "pmb:kconfigcheck-…" options for APKBUILDs. Generate it from the kconfigcheck.toml of the current branch, too.

These options are passed from "pmbootstrap lint" to "apkbuild-lint", which we run in pmaports CI.

Related: pmaports!5633

pmb/config/__init__.py

@@ -283,17 +283,12 @@ apkbuild_attributes = {
 }
 
 # Reference: https://postmarketos.org/apkbuild-options
+# In addition to these, pmbootstrap adds "pmb:kconfigcheck-community" etc.
+# dynamically based on kconfigcheck.toml in the currently checked out pmaports
+# branch
 apkbuild_custom_valid_options = [
     "!pmb:crossdirect",
     "!pmb:kconfigcheck",
-    "pmb:kconfigcheck-community",
-    "pmb:kconfigcheck-containers",
-    "pmb:kconfigcheck-iwd",
-    "pmb:kconfigcheck-netboot",
-    "pmb:kconfigcheck-nftables",
-    "pmb:kconfigcheck-uefi",
-    "pmb:kconfigcheck-waydroid",
-    "pmb:kconfigcheck-zram",
     "pmb:cross-native",
     "pmb:gpu-accel",
     "pmb:strict",