Update LibRASR: Add lazy logging initialization and explicit init_logging function

[SimBe195]

Currently, when librasr is imported in Python, a DummyApplication is created which initializes a channel manager for logging. Since no config files can be passed to librasr at that point yet, the DummyApplication uses an empty config for this and only sets the encoding to "utf-8" (hardcoded). This makes it impossible to configure the channels (e.g. setting unbuffered = yes or similar things). This PR overhauls this mechanism. A pybind function librasr.init_logging(config) is added and instead of creating the channel manager immediately upon import, this is done when either init_logging is called or lazily when logs need to be written. This makes it possible to pass user config for the channel manager like this:

import librasr
config = librasr.Configuration()
config.set_from_file("rasr.config")
librasr.init_logging(config)

if init_logging is never called, the behavior stays the same, i.e., as soon as components start logging things, a channel manager is created with default parameters.

The PR also removes initRASR and finiRASR from src/Tools/LibRASR/LibRASR.cc which dont't seem to have a purpose (anymore) and are never called anywhere.

[larissakl]

@SimBe195 If you have time, could you maybe directly add a short bullet point explaining this in the new documentation (should go under section "Using SearchV2 from Python" -> "Configuration object")?

[curufinwe]

LGTM, but let's merge only after #250 is merged as you included it in this PR.