build: remove some things not used in Evervolv

core: we don't use backuptool on evervolv

Revert "Store the base64 release key in the OTA zips"

This reverts commit b8468559ab46bd6bc75487e75c8071adf42e8286.

Revert "tools: getb64key - print the base64 version of a PEM public key file"

This reverts commit 360e233962b7f28638dc274f7c09bf08689db0e0.

Revert "For user builds, use a release build id in the description if one exists"

This reverts commit a44621c019d0de5488ba9cc991f0e9fec1732985.

Revert "Sign final packages with a different key if requested"

This reverts commit 6f35c1683f6907f6b8f8d136f000ccbee289c68f.

Change-Id: Ief6ec641540e15ff0438c8edfe6b54935d213614