to update descriptions and format of the GNSSRO Rmatrix

[hailingz]

Description

The description and format of the GNSSRO R matrix files can use some improvement, clean up and format check.
For example, the R matrix for bending angle is described as for refractivity.
There are also many duplications of the same description for each satellite entry as below.

! Each entry is for a given range of latitudes, and the nearest matrix to each
! observation will be chosen.
! The observation errors are given for a set of heights.
! If an observation is present on a height outside this range, then the value
! will be taken to be the value at the relevant end.
! If an observation is at a height between the levels indicated, then the code
! will linearly interpolate between those heights.
! The entries are given as relative errors (percentage error of the observation
! divided by the background bending angle).

Acceptance Criteria (Definition of Done)

Reviewers' approval for non-code changes.

Dependencies

N/A