Draft: Tidy GMRES output and capture scientific notation

Issue/feature addressed

Tidy GMRES' verbose output to make it similar to CG's output.

Proposed solution

Remove additional whitespaces and avoid escaping the scientific notation such that all output is switched to scientific notation. I removed the REAL eps result, because it seems always equal to the GMRES eps. Happy for any comments here.

Implementation

Previously:

CG iterations made = 35 using tolerance of 0.0001 (error = 9.03826e-05, rhs_mag = 42.9255)
       GMRES iterations made = 75 using tolerance of 1.00000e-04 (error = 8.94376e-05) WITH (GMRES eps = 7.99909e-09 REAL eps= 7.99909e-09) CONVERGED

Now:

CG iterations made = 35 using tolerance of 0.0001 (error = 9.03826e-05, rhs_mag = 42.9255)
GMRES iterations made = 75 using tolerance of 0.0001 (error = 8.94376e-05, rhs_mag = 1 with (GMRES eps = 7.99909e-09) CONVERGED

Tests

Suggested reviewers

@CFD-Xing

Notes

• Slightly controversial because people's scripts to read the log files might need fixing.

Checklist

• Functions and classes, or changes to them, are documented.
• User guide/documentation is updated.
• Changelog is updated.
• Suitable tests added for new functionality.
• Contributed code is correctly formatted. (See the contributing guidelines).
• License added to any new files.
• No extraneous files have been added (e.g. compiler output or test data files).