Modernize python and update pylint (#5096)

Update code to conform to the newer version of pylint available in
ubuntu-22.04, with few exceptions:
    - disabled `import-outside-toplevel` for `main()` in
      `jerry_client.py`
    - disabled `consider-using-with` for the logfile of `TestSuite` in
      `test262-harness.py` as using `with` is not practical in that case

Update test262-harness.py to use argparse instead of the now deprecated
optparse

Rename variables in jerry_client_main.py that redefined python builtins
or shadowed variables from an outer scope

Update python files to use f-stirngs

Add minimum python versions (3.6 and 3.8) to the CI jobs: without it the
default python version did not support the `with` statement for
`subprocess.Popen` used in `build.py` on macos, or in some cases f-stirngs

Remove `from __future__` imports that are no-ops in python 3

Remove shebang from non executable files

Re-enable most pylint checkers, except `missing-docstring`

JerryScript-DCO-1.0-Signed-off-by: Máté Tokodi mate.tokodi@szteszoftver.hu

tools/check-license.py

@@ -14,8 +14,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from __future__ import print_function
-
 import io
 import os
 import re
@@ -78,9 +76,9 @@ def main():
             for fname in files:
                 if any(fname.endswith(ext) for ext in EXTENSIONS):
                     fpath = os.path.join(root, fname)
-                    with io.open(fpath, 'r', errors='ignore') as curr_file:
+                    with io.open(fpath, 'r', errors='ignore', encoding='utf8') as curr_file:
                         if not LICENSE.search(curr_file.read()):
-                            print('%s: incorrect license' % fpath)
+                            print(f'{fpath}: incorrect license')
                             is_ok = False
 
     if not is_ok: