Fixes for UI arch and compute-resource related test-cases.

* Reformat docstrings to make them more compact.
* Drop length arguments to `gen_*` methods. They produce 10 character long strings by default, which is fine.
* Remove generic exception and use UINoSuchElementError instead.
* Fixed arch.delete locator for architecture entity.
* And many other miscellaneous fixes.
Added test for environment update
Merge pull request #1801 from kbidarkar/fix-arch-tests

Fixes for UI arch and compute-resource related test-cases.
Merge pull request #1798 from tkolhar/test_cli

Added test for environment update
Fixed some UI tests related to hw_model, p_table and hostgroups.

* Updated data as per tests.
* Drop length arguments to `gen_*` methods. They produce 10 chars
  long strings by default
* Removed skips related to old bugs.
* Many other miscellaneous fixes.
Merge pull request #1804 from kbidarkar/fix-ui-tests1

Fixed some UI tests related to hw_model, p_table and hostgroups.