De MRC Auto get Metadata

[CSSFrancis]

Description of the change

A few sentences and/or a bulleted list to describe and motivate the change:

• [x] Fix a bug with the newest version of DE Server (Some of the metadata "Keys" were changes)
• [x] Add auto determination of the metdata_info.txt file based on the naming scheme.

Progress of the PR

• [x] Change implemented (can be split into several points),
• [ ] update docstring (if appropriate),
• [ ] update user guide (if appropriate),
• [ ] add a changelog entry in the upcoming_changes folder (see upcoming_changes/README.rst),
• [ ] Check formatting of the changelog entry (and eventual user guide changes) in the docs/readthedocs.org:rosettasciio build of this PR (link in github checks)
• [ ] add tests,
• [ ] ready for review.

Minimal example of the bug fix or the new feature

from rsciio.mrc import file_reader
file_reader("your_mrc_file.mrc") # new automatically finds metadata file
file_reader("your_mrc_file.mrc", metadata_file = "your_mrc_file_info.txt ") # old

Note that this example can be useful to update the user guide.