Merge changes from topic "lts-v2.8.10" into lts-v2.8

* changes:
  docs(changelog): changelog for lts-v2.8.10 release
  fix(fvp): increase BL2 size for CRYPTO_SUPPORT & ROMLIB
  feat(libc): add %c to printf/snprintf
  feat(docs): update Mbed-TLS version to v2.28.5
  fix(docs): use rsvg-convert as the conversion backend
  fix(docs): fix build errors for latexpdf
  chore(docs): reformat sphinx configuration
  fix(docs): add missing click dependency
  fix(docs): pin poetry to version used in CI
  feat(docs): add support for poetry
  fix(docs): add plantuml as a dependency
  fix(docs): python version must be string
  fix(docs): specify python version to 3.10
  fix(docs): add a build.tools.python entry
  fix(docs): add readthedocs configuration file