* Container OS upgrade from SL7 to RL8
* gcc 4.8.5 --> gcc 9
* `specfile` package builds and installs on EL7 and RL8

Breaking changes:

* `lalapps_inspinj` not included (still part of `lalapps`)
* ???

add injections option to offline dag

- perform density estimation and normalization to zero-lag counts

- rename --candidate-cache to --candidates-cache

- can load multiple rankingstat files

- don't round injections to integer seconds
- set random sky locations
- set random polarizations

- rename --likelihood-cache to --ranking-stat-cache

- rename --candidate-cache to --candidates-cache
- add --ranking-stat-cache

- not needed just being done for safety

- snr^-7 for 1/r flux density

	- change sample rate from 2048 to 8192
	- add FIXME on timeslide
	- don't forget to record the process end time

- Histogram zero-lag candidates' likelihood ratio

- It calculates the likelihood ratio for zero lag candidates

 - Change the plot range for x and y axis
 - add rankingstat.finish() for normalization and kde estimation because such function is added to rankingstat.py

gstlal_cherenkov_calc_rank_pdfs: Removing RankingststPDF class from gstlal_cherenkov_calc_rank_pdfs to cherenkov/rankingstat.py

 - add calculation on PDF
 - add functions
 - add RankingstatPDF class for utility

gstlal_cherenkov_burst: make it importing CoincDef from cherenkov module for the later use on gstlal_cherenkov_zl_rank_pdfs

gstlal_cherenkov_inj: make it possible to generate multiple injections with randomlt generated amplitude and other input parametes in the defined range.

- between trigger generator, coincidence code, and ranking statistic recorder