More cleanup in providerHelper
PgpSignEncrypt: get by master key id
PgpSignEncrypt: merge generateSignature() into main method
PgpSignEncrypt is now context-free
put signatureType where it belongs
PgpDecryptVerify is now context-free
Simplify and fix delete key dialog
Remove some Ids...
More fixes for import item layout
More ids removed
Clarify use of methods in PgpKeyHelper
PgpSignEncrypt comment