Support for disabling conversation mode

[rosecitytransit]

Mentioned in #791 and is a follow up to #326

I've thought the recording mode should be at least a 3 way option.

Upon termination flag (transmission end):

• call is always closed, putting each transmission in a separate call (future transmissions are started based upon their grant messages by ignoring check for existing call)
• (current mode) file is closed but call is kept open
• file is kept open and closed on call end

To do conversation mode only involves:

1. not closing the file in end_transmission() here https://github.com/robotastic/trunk-recorder/blob/e33e441278ae130a6884d464a5d75b97655ca5fd/trunk-recorder/gr_blocks/transmission_sink.cc#L224
2. adding close_wav() to stop_recording() https://github.com/robotastic/trunk-recorder/blob/e33e441278ae130a6884d464a5d75b97655ca5fd/trunk-recorder/gr_blocks/transmission_sink.cc#L257 since end_transmission() will no longer do it
3. having a separate sample counter so that close_wav() creates a correct header
4. Ignoring or removing the error messages about the file not closing/being open
5. modifying call concluder to handle the entire call being in the first transmission file
6. Also need to move https://github.com/robotastic/trunk-recorder/blob/ca64f7a7f5aa48ac82196b43b3d04700f5825051/trunk-recorder/gr_blocks/transmission_sink.cc#L546-L547 outside of transmission_sink::dowork because on a termination flag they will not be reached due to https://github.com/robotastic/trunk-recorder/blob/ca64f7a7f5aa48ac82196b43b3d04700f5825051/trunk-recorder/gr_blocks/transmission_sink.cc#L483

Originally posted by @rosecitytransit in #791 (comment)

[robotastic]

Keeping the current approach - it is a good balance of keeping the number of files reasonable and not having to move file pointers around too. Happy to reconsider if there is a strong desire for this

[robotastic]

Actually... maybe we should enable some support for turning off conversation mode.... I will leave this open

[mikecomer-beakon]

Have you thought about doing this for talkgroups too not just system level?

[robotastic]

Ok - I went through the code a little. I forgot that with the new method of handling transmissions, everything is already chopped up into single transmissions and then merged back together at the end. To enable this we just need to not merge things together, and then just batch run the plugins on each file.

I will look to set it up so it can either be configured at the system level or by talkgroup

[robotastic]

Ok - I just kicked off a branch - it compiles but has not been tested yet. It only has support for a system level setting currently:
https://github.com/TrunkRecorder/trunk-recorder/tree/dev/conversation

[robotastic]

Ok - if folks can give this a try, that would great. @mikecomer-beakon I added in support for defining this at the talkgroup level and the system level. You can turn it on/off at the System Level, by adding conversationMode=true/false to a system in the config file. You can also override that at the Talkgroup level. Just add a "Conversation Mode" column to the talkgroups csv and define it for the TGs you are interested in.