do not tag read only segments any more

Problem: Normally a term tagging of read only segments is not necessary, since the user is not able to change / fix terminology there.

Currently also readonly segments are tagged, which wastes CPU usage, also some projects are containing segments with context data, not to be translated, which are marked readonly. This segments are sometimes really huge, slowing down the import. Also it may happen that, they are less then 150 words (>150 words are considered as huge segments and are therefore not tagged) and depending on the CPU usage the nearly 150 word segments need longer as the configured timeouts.

Solution:

By default read only segments are not tagged anymore. This can be changed by config.