Re-do first paragraph of 'contributing packages'.

[shloka-gupta]

PR Checklist:

• [X] make all edits to the docs in the src directory, not in docs or in the html files
• [ ] note any issues closed by this PR with closing keywords
• [X] put any other relevant information below

The first paragraph of 'contributing packages' seemed to require clarity. The PR tries to give a clearer picture by giving the title 'Process' to the paragraph and further divides the already existing paragraph into steps so that a person submitting a package knows where they stand.

The outcome:

PS: I haven't created an issue for the PR and it would be really great if someone could suggest how to make it look better.

[shloka-gupta]

Hi @beckermr @kathatherine and @BastianZim hope this PR is helpful. Would appreciate your feedback.

[shloka-gupta]

@kathatherine I have made the changes. A few pointers, I felt adding about the roles of the maintainer in the Process as well as in the Maintainer role was redundant. What do you think?