[DAQ-474] convert ScanPointsWriter to SolsticeScanMonitor

[mpdickie]

which now implements IScannable

[gerring]

SonarQube analysis reported 4 issues

Note: The following issues were found on lines that were not modified in the pull request. Because these issues can't be reported as line comments, they are summarized here:

1. SolsticeScanMonitor.java#L137: This block of commented-out lines of code should be removed.
2. SolsticeScanMonitor.java#L203: At most one statement is allowed per line, but 2 statements were found on this line.
3. SolsticeScanMonitor.java#L241: Define and throw a dedicated exception instead of using a generic one.
4. SolsticeScanMonitor.java#L138: Complete the task associated to this TODO comment.