avoid throwing sql exceptions in logtimeFunction

[kortemik]

currently logtimeFunction throws in case SUBSTRING does not return a valid timestamp for STR_TO_DATE. this is currently mitigated by having jooq setting throw-none enabled in some environments.

pth_06/src/main/java/com/teragrep/pth_06/planner/StreamDBClient.java

Lines 320 to 324 in 2b251b1

	public final Field<Long> logtimeFunction = DSL
	.field(
	"UNIX_TIMESTAMP(STR_TO_DATE(SUBSTRING(REGEXP_SUBSTR({0},'^\\\\d{4}\\\\/\\\\d{2}-\\\\d{2}\\\\/[\\\\w\\\\.-]+\\\\/([^\\\\p{Z}\\\\p{C}]+?)\\\\/([^\\\\p{Z}\\\\p{C}]+)(-@)?(\\\\d+|)-(\\\\d{4}\\\\d{2}\\\\d{2}\\\\d{2})'), -10, 10), '%Y%m%d%H'))",
	Long.class, JOURNALDB.LOGFILE.PATH
	);

a better approach would be to return return a date that does not match i.e. 1970010100 from the SUBSTRING in case it was unable to perform the extraction.