new_rde_data_line_re.search() stalls

[interplanetarychris]

This was previously TruSat/trusat-backend#26 as follows:

Following unit test updates, both SeeSat archive import scripts appear to be "paused," in a Ctrl-S terminal way, in the process of importing. Ctrl-C in the terminal allows them to continue, but it is unclear what is the underlying cause, or if data loss happens because of the Ctrl-C.

Debugger sessions have yet to refine the location of the problem itself.

From terminal feedback with the -V flag:
https://github.com/consensys-space/trusat-backend/blob/257bf4606147dbd927f3c3b9acf453b475c22656/database_tools/read_seesat_mbox.py#L346

...the script appears to consistently "pause" after the following lines:

Found  67 IOD obs in msg: 2015-03-19 23:23:00+01:00 LB Obs 2015 Mar 19
Found 162 IOD obs in msg: 2018-04-21 10:05:40+02:00 LB Obs 2018 Apr 20-21 night
Found   2 IOD obs in msg: 2019-03-27 22:56:50+01:00 Obs 2019 Mar 27 pm
Found   3 IOD obs in msg: 2019-09-20 07:28:25-04:00 slow moving unid seen on Sept 19

and has been traced to the following regex in iod.py:

https://github.com/consensys-space/trusat-orbit/blob/ea82c90af2645183318f7fc716a901960e0d5c65/iod.py#L760-L784

Re-writing the regex with no extraneous whitespace (to disallow the OR'ed flags for re.MULTILINE and re.VERBOSE) did not solve the problem.

It could be due to a problem with exponential possibilities on possible matches, referenced in https://bugs.python.org/issue29977

An interim "solution" is to use the previous RDE-block matching regexp (rde_format_re), which is not as comprehensive.

[interplanetarychris]

For reference, when importing the hypermail seesat archive, the older version of the regexp results in:
Processed 402373 observations in 81021 files in 25 directories.
(277864) IOD records (69.06 %)
(42221) UK records (10.49 %)
(82288) RDE records (20.45 %)

[interplanetarychris]

For reference in MBOX processing:
Processed 201211 observations in 12773 messages in 21.705 seconds.
(176197) IOD records (87.6 %)
( 3589) UK records ( 1.8 %)
( 21425) RDE records (10.6 %)

Last messageID imported from: 51831162-2d47-7577-ee1d-0f8bcc60fb00@blueyonder.co.uk