Fix problems with tools

[mkavulich]

NOTE: This is a draft until #143 is merged, as it contains the same commits

Description

In the process of trying to add a new tool to check for redundant CF name elements (see #143), I found that our existing tools suffer from a number of issues:

• Several tools were not updated appropriately to deal with nested sections (Changes after rename of CCPPStandardNames --> ESMStandardNames #98) so they are not properly checking all the names in the dictionary
  • This meant that there were several redundant standard names that had to be removed
• A bad merge at some point re-introduced some non-working code from the framework in tools/write_standard_name_table.py; since doctests are not used in this repository, I removed those tests and the un-exercised logic
• Changes in Remove version information from schema filename, remove obsolete features #142 that standardized the spelling of the schema file left a lot of stub logic that should be removed

This PR resolves those problems. Also, I took the opportunity to clean up the existing tools:

• Make all python scripts pass pylint with a 10/10 score
  • Removed all old format strings, replacing with f-strings (Update python scripts to use f-strings #118)
• Standardized the format of comments and multi-line strings
• Standardized how command-line arguments are named and referenced
• Removed many unnecessary comments

And finally, I added the check for duplicate cfname elements that was the start of this whole process.

Issues

Resolves #118, #144