FEO example readme files are outdated

### Description

FEO readme files in the example subdirectory are outdated.

### Analysis results

Cargo build is no longer supported, so the explanations must be changed towards use of bazel.

### Solution

Update readme files

### Error Occurrence Rate

None

### How to reproduce

_No response_

### Supporting Information

_No response_

### Classification

minor

### Affected Version

pre-0.5

### Expected Closure Version

0.5

### Category

- [ ] Safety Related
- [ ] Security Related

### ASIL classification

_No response_