Add universal build_type variant to CMakePackage (#4797)

* Add universal build_type variant to CMakePackage
* Override build_type in some packages with different possible values
* Remove reference to no longer existent debug variant
* Update CBTF packages with new build_type variant
* Keep note on build size of LLVM

var/spack/repos/builtin/packages/flecsale/package.py

@@ -33,7 +33,6 @@ class Flecsale(CMakePackage):
 
     version('develop', git='https://github.com/laristra/flecsale', branch='master', submodules=True)
 
-    variant('debug', default=False, description='Build debug version')
     variant('mpi', default=True,
             description='Build on top of mpi conduit for mpi inoperability')
 
@@ -43,13 +42,6 @@ class Flecsale(CMakePackage):
     depends_on("python")
     depends_on("openssl")
 
-    def build_type(self):
-        spec = self.spec
-        if '+debug' in spec:
-            return 'Debug'
-        else:
-            return 'Release'
-
     def cmake_args(self):
         options = [
             '-DENABLE_UNIT_TESTS=ON'