Remove redundant str() calls and prefer !r marker for repr in formatting

[Avasam]

As title says:

• prefer more succint {!r} over repr
• avoid unnecessary calls to str() and repr()

Will also reduce changes in #2223

Expecting a few slight behaviour changes: " vs ' in some strings where it should not matter, especially in traces, logs, debugging, tests, etc.

[vernondcole]

Edits in adodbapi subsystem look great. Will this merge cleanly with the adodbapi branch? I suspect that it will.
I am still experimenting with a set of VMs that can do a proper test of adodbapi. My entire development system these days is on Linux, so testing Windows stuff is a challenge. I suspect that the final result will be something that we can eventually add as an option to the CI build system.

[Avasam]

Hi @vernondcole ! I meant to split adodbapi changes as I usually do to make it easier for you and Mark to review without depending on each other! I'll go and split this off right now.

Will this merge cleanly with the adodbapi branch?

Maybe, maybe not, but I'm usually pretty quick about fixing any conflict. You can merge any current adodbapi PR in any order you want.

Edit: There you go: #2276