Fix markdownlint and shellcheck errors

This commit addresses issues with markdownlint complaining
about unspecified languages for the fenced code blocks in
the README.md files of the main repo and the dreport tool.

Resolved this by specifying 'bash' as the language for
these code blocks in both README.md files.

Additionally added tools/dreport.d/ibm.d/plugins.d/badpel
to .shellcheck-ignore to suppress SC1091 and SC2086
errors

Change-Id: I3432dc87999f518949a9459d2ab07e21a73595b1
Signed-off-by: Dhruvaraj Subhashchandran <dhruvaraj@in.ibm.com>