Allow running pylint and mypy on a single file

Fix `mypy scripts/xxx.py`, `mypy tests/scripts/xxx.py`,
`pylint scripts/xxx.py`, `pylint tests/scripts/xxx.py`
failing to find `mbedtls_framework`.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>

.mypy.ini

 [mypy]
-mypy_path = scripts
+mypy_path = framework/scripts:scripts
 namespace_packages = True
 warn_unused_configs = True

.pylintrc

 [MASTER]
-init-hook='import sys; sys.path.append("scripts")'
+init-hook='import sys; sys.path.append("scripts"); sys.path.append("framework/scripts")'
 min-similarity-lines=10
 
 [BASIC]