allow topic to be encapsulated in quotes

[bodeme]

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Also created this fix based on the develop-branch with slightly changed calls (REQUIRE_NON_EMPTY_OPTION, mosquitto_malloc with one underscore)

[bodeme]

Fixes #1756 Fixes #658

[ralight]

Thank you, this is fixed in https://github.com/eclipse-mosquitto/mosquitto/commit/2370415a3fa2e667eb22325e485c22ca3e030388 and the following commit for the 2.1 release