Fix date-related Resources test errors; do other fixes

[seav]

Proposed changes in this pull request

This PR's main intention is to fix functional test failures encountered in the latest PRs in the cadasta-platform repo. This PR also fixes some smaller encountered bugs.

• Update the package version to 0.6.1.
• Update the generation of dates that are used for resources date comparison. This is the source of the errors encountered in the latest cadasta-platform PRs.
  • Cause: It was previously assumed that Django by default generated month names in a standard abbreviated format like Jan. and Feb. containing the month's first three characters followed by a period. However for months with short names (March, April, May, June, July) the name is no longer abbreviated, and for September, the name is abbreviated with 4 characters (Sept.).
• Update the usage of <element>.find_element_by_xpath() to make use of relative XPath instead of absolute XPath.
  • The intention of this method call is to search by XPath within the specified element but the XPath used was absolute (starts with /) instead of relative to the current element (starts with .). See docs.
• Update some XPaths to refer to the resource name instead of the resource filename.
  • Since the generated resource name is random, this is essentially guaranteed to be unique as opposed to the filenames which are limited in number (we only have a small number of test files and we reuse them as needed). This makes the XPath target the intended element better.
• Update the generated random resource name random part to be 12 characters instead of 24.
  • Long resource names make the resources table too wide and this sometimes pushes the "Detach" button partially or fully off the screen causing the #D1 test case to fail.

When should this PR be merged

ASAP. The date-related errors is a blocker for PRs in the cadasta-platform repo.

Risks

None foreseen.

Follow-up actions

• Release as v0.6.1.
• Update cadasta-platform to refer to this release.

Checklist (for reviewing)

General

• Is this PR explained thoroughly? All code changes must be accounted for in the PR description.
• Is the PR labeled correctly? It should have the migration label if a new migration is added.
• Is the risk level assessment sufficient? The risks section should contain all risks that might be introduced with the PR and which actions we need to take to mitigate these risks. Possible risks are database migrations, new libraries that need to be installed or changes to deployment scripts.

Functionality

• Are all requirements met? Compare implemented functionality with the requirements specification.
• Does the UI work as expected? There should be no Javascript errors in the console; all resources should load. There should be no unexpected errors. Deliberately try to break the feature to find out if there are corner cases that are not handled.

Code

• Do you fully understand the introduced changes to the code? If not ask for clarification, it might uncover ways to solve a problem in a more elegant and efficient way.
• Does the PR introduce any inefficient database requests? Use the debug server to check for duplicate requests.
• Are all necessary strings marked for translation? All strings that are exposed to users via the UI must be marked for translation.

Tests

• Are there sufficient test cases? Ensure that all components are tested individually; models, forms, and serializers should be tested in isolation even if a test for a view covers these components.
• If this is a bug fix, are tests for the issue in place? There must be a test case for the bug to ensure the issue won’t regress. Make sure that the tests break without the new code to fix the issue.
• If this is a new feature or a significant change to an existing feature? has the manual testing spreadsheet been updated with instructions for manual testing?

Security

• Confirm this PR doesn't commit any keys, passwords, tokens, usernames, or other secrets.
• Are all UI and API inputs run through forms or serializers?
• Are all external inputs validated and sanitized appropriately?
• Does all branching logic have a default case?
• Does this solution handle outliers and edge cases gracefully?
• Are all external communications secured and restricted to SSL?

Documentation

• Are changes to the UI documented in the platform docs? If this PR introduces new platform site functionality or changes existing ones, the changes must be documented in the Cadasta Platform Documentation.
• Are changes to the API documented in the API docs? If this PR introduces new API functionality or changes existing ones, the changes must be documented in the API docs.
• Are reusable components documented? If this PR introduces components that are relevant to other developers (for instance a mixin for a view or a generic form) they should be documented in the Wiki.