Clean up miscellaneous code smells, eliminate most Guava use

[dbwiddis]

Description

Eliminated unnecessary throwing of IOException on workflow steps execution, left over from when we did more parsing in the steps.

Used a linter based on SonarQube analysis and fixed up lots of little things.

• Used inline replacements for the logger rather than concatenation
• Better handling of conditionals
• Avoiding variable name collisions
• Replacing functional interfaces with shorter syntax (mostly () -> context.restore() to context::restore)

Eliminated most use of Google Guava, which have been mostly useless since Java 9, specifically:

• ImmutableList.of replaced by Java's List.of or Collections.emptyList() when empty
• ImmutableMap.of replaced by Java's Map.of for 2 elements and Map.ofEntries for more than one pair, or Collections.emptyMap() if empty.
• Charset replaced by Java's StandardCharsets
• Did not remove the Resource.toString() yet as it's a bit more complex and should be handled in a separate PR. See issue [FEATURE] Eliminate all use of Google Guava #328

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
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[ohltyler]

LGTM, nice cleanup!

[opensearch-trigger-bot]

The backport to 2.x failed:

The process '/usr/bin/git' failed with exit code 128

To backport manually, run these commands in your terminal:

# Navigate to the root of your repository
cd $(git rev-parse --show-toplevel)
# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add ../.worktrees/flow-framework/backport-2.x 2.x
# Navigate to the new working tree
pushd ../.worktrees/flow-framework/backport-2.x
# Create a new branch
git switch --create backport/backport-327-to-2.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 89c03f9dd094f37575ad43ae8d57fc8b5982329c
# Push it to GitHub
git push --set-upstream origin backport/backport-327-to-2.x
# Go back to the original working tree
popd
# Delete the working tree
git worktree remove ../.worktrees/flow-framework/backport-2.x

Then, create a pull request where the base branch is 2.x and the compare/head branch is backport/backport-327-to-2.x.